flow fields, unit behavior graphs, performance boosts

Merge pull request #1611 from heinezen/release/changelog-0.5.3

Changelog release 0.5.3

Merge pull request #1581 from heinezen/release/changelog-0.5.2

Changelog release `0.5.2`

Merge pull request #1567 from heinezen/doc/release-0.5.1

Changelog release `0.5.1`

Merge pull request #1531 from heinezen/changelog-0.5.0

doc: Changelog v0.5.0

last release before lockstep removal

lots of stuff, I lost track

Merge pull request #1121 from xcom169/patch-1

Add OpenSAGE to the list

Major refactoring that adds tons of internal features and a few new v…

…isible features.

 * New language versions: Python 3.4, C++14, Cython 0.22
 * Python code is now compliance-checked via pylint
 * Integrated various code sanitizers and the clang static analyzer
 * C++ <-> Python function calling interface, based on Cython
 * Proper and integrated C++ and Python logging subsystem
 * Dumped GLEW for libepoxy
 * Keybindings manager
 * New C++ and Python testing system

Visible features:

 * Unified program entry point
 * Asset conversion automatically runs when launching the game
 * Units can perform various commands
 * Units actively search for new commands
 * Units can fight
 * Mode indicator

Whee, another release you've all been waiting for!

New shiny stuff:
* Walking units
* Pathfinding
* Profiling
* Inotify asset refreshing
* First drafts for nyan
* Terrain debug grid (F4)
* Unit creation and death sounds
* Mac OSX support
* AOE:HD support

Improvements:
* Buildsystem heavily boosted
* Gamespec loading job in background
* Random things all over the code