This file collects the significant changes to the book since its initial public release.

### Version 0.5.0

Lots of attention after too long.

  * Book now builds automatically via CircleCI.  This is a big improvement because it means
    that commits and pull requests can be automatically built and deployed.  In practice,
    I may not redeploy on every commit, but at least the tool chain is now solid enough
    that we can be sure lots of manual updates to tools won't be required.

  * Removal of client-side simulations.  In 2014, I was optimistic that the tools required
    to produce Javascript for all simulations would stabilize.  Unfortunately, it hasn't.
    The instability in those tools was impacting the stability of the build process for
    the book.  As such, I've removed client side simulation.  Although it was pretty 
    cool, it actually had two problems.  First, it was slower (than the new server-side
    simulation).  Second, it was an issue on mobile devices because of memory required
    in the browser.  The new approach has a minimal browser footprint so should lead
    to faster load times, faster simulations and availability across all platforms.

  * A root level Makefile was added that allows the entire book to be built requiring
    only Docker and Node to be installed.

### Version 0.3.6

#### Enhancements

  * Addressed
    [an issue](https://github.com/xogeny/ModelicaBook/issues/205) with
    the discussion on chattering.  Resulted in a fair amount of
    reworking.  But I think it demonstrates the issue better. Thanks
    to @sjoelund for pointing that out and his suggestions.

  * Several enhancements related to creation of eBook versions were
    added by @dietmarw.

  * Merged https://github.com/xogeny/ModelicaBook/pull/208

  * Tried to address
    [@tbeu's concerns](https://github.com/xogeny/ModelicaBook/issues/146)
    about Linux dependencies.

#### Bug Fixes

  * Addressed some issues with wording not being updated in
    [issue #210](https://github.com/xogeny/ModelicaBook/issues/210)

  * Merged pull requests for
    [a](https://github.com/xogeny/ModelicaBook/pull/209)
    [few](https://github.com/xogeny/ModelicaBook/pull/211)
    [more](https://github.com/xogeny/ModelicaBook/pull/215) typos.

### Version 0.3.5

#### Enhancements

  * Incorporated [a](https://github.com/xogeny/ModelicaBook/pull/196)
    [number](https://github.com/xogeny/ModelicaBook/pull/198)
    [of](https://github.com/xogeny/ModelicaBook/pull/199)
    [nice](https://github.com/xogeny/ModelicaBook/pull/200)
    [pull](https://github.com/xogeny/ModelicaBook/pull/201)
    [requests](https://github.com/xogeny/ModelicaBook/pull/202) from
    Thomas Beutlich (@tbeu) that improved the quality of the text,
    images and the models.

  * Added a note about non-linear and time-variant models to the
    discussions in the section on state space representations.  This,
    again, the result of a
    [discussion](https://github.com/xogeny/ModelicaBook/issues/135)
    with Thomas Beutlich @tbeu.

  * At @dietmarw's request, I added a few more examples to the
    discussion of array related functions.

#### Bug Fixes

  * Added missing figure in discussion on one-dimensional heat
    transfer using arrays.

### Version 0.3.4

#### Enhancements

  * Greatly improved structure for PDF.  This is all thanks to Dietmar Winkler
    (@dietmarw) who restructured many things to give the PDF version a more
	proper structure that includes parts, chapters and sections.

### Version 0.3.3

#### Enhancements

  * Made the first few plots in the discussion of state events NOT
    interactive.  This is because they are showing results of problematic
    simulations that don't run well in the browser.

  * Clarification of heater output plot in discussion of hysteresis.

  * Emphasized the use of equations over algorithms in discussion on
    hysteresis.

  * Added padding and the end of the HTML body so page doesn't end abruptly

  * Added discussion of the ``smooth`` operator (issue
    [#188](https://github.com/xogeny/ModelicaBook/pull/188))

#### Bug Fixes

  * Completed discussion of synchronous clock features in section on Sampling.

  * Completed table that discusses the relationship between events and
    various functions/operators (issue
    [#187](https://github.com/xogeny/ModelicaBook/pull/187))

  * Used a consistent heat transfer formulation throughout the book (issue
    [#150](https://github.com/xogeny/ModelicaBook/pull/150))

  * Added review of missing clock related functions
  
### Version 0.3.2

#### Enhancements

  * Improved discussion of initial conditions to mention the `fixed`
    attribute (issue
    [#133](https://github.com/xogeny/ModelicaBook/pull/133))

#### Bug Fixes

  * Added missing explanation of annotation structure
  * Added an explanation of `record` constructors (issue
    [#60](https://github.com/xogeny/ModelicaBook/pull/60), opened by
    @casella)
	
### Version 0.3.1

#### Enhancements

  * Improved visibility for search engines
  * Simplified README (issue [#151](https://github.com/xogeny/ModelicaBook/pull/151))
  * Improved highlighting (thanks to [@dietmarw](https://github.com/dietmarw) and the
    newest version of Pygments)

#### Bug Fixes

  * Fixed non-standard annotation (issue [#155](https://github.com/xogeny/ModelicaBook/pull/155))
  * Fixed sponsor links (issue [#160](https://github.com/xogeny/ModelicaBook/pull/160))

### Version 0.3.0

#### Enhancements

  * Moved the site to [book.xogeny.com](http://book.xogeny.com) with redirects
    from beta site.
  * Lots of cleanup of annotations by [@tbeu](https://github.com/tbeu) and
    [@dietmarw](https://github.com/dietmarw)
  * Switched back to using MathJax (looks nicer, but requires JS)
  * Updated the README to help orient people who want to contribute.
  * Incorporated a bunch of excellent fixes and improvements from
    @mrtiller related to
    [#42](https://github.com/xogeny/ModelicaBook/pull/42/files).

#### Bug Fixes

  * Merged a the following pull requests from [@tbeu](https://github.com/tbeu):
	[#143](https://github.com/xogeny/ModelicaBook/issues/143),
	[#142](https://github.com/xogeny/ModelicaBook/issues/142),
	[#141](https://github.com/xogeny/ModelicaBook/issues/141),
	[#139](https://github.com/xogeny/ModelicaBook/issues/139),
	[#137](https://github.com/xogeny/ModelicaBook/issues/137),
	[#117](https://github.com/xogeny/ModelicaBook/issues/117) and
	[#93](https://github.com/xogeny/ModelicaBook/issues/93)
  * Merged a change from [@tbeu](https://github.com/tbeu) regarding a heat
    transfer example in the discussion on packages.
  * Merged a bunch of changes from [@tbeu](https://github.com/tbeu) that improve
    the external function examples and clean up a few other things.
  * Fixed an error in the source code for the 1D heat conduction
    equation examples and fixed a recurring error (see issue
    [#53](https://github.com/xogeny/ModelicaBook/issues/53)) in the
    equations presented along with the source code.
  * Fixed issue
    [#61](https://github.com/xogeny/ModelicaBook/issues/61) which
    involved a misplaced annotation.
  * Fixed an error in one of the Lotka-Volterra equations raised
    in issue [#50](https://github.com/xogeny/ModelicaBook/issues/50).
  * Corrected the explanation on the `unit` attribute raised in
    [#59](https://github.com/xogeny/ModelicaBook/issues/59)


### Version 0.2.0

  * Early access release, first official public version.

