background, blocks & frame; AP-174
Blocks and Map; AP-174 & AP-179
Added map-class to Game.cpp (Minor changes to block and map).
Comment interfaces
Add simple test and get it to run. AP-181
Add unit tests to ICoreSystem. AP-175

Warning! Breaks windows build. Really.
Add a few more tests. AP-181
updated ball collision to be a little less sucky (but still kind of sucky)
Small refactor to improve handling of CoreSystem objects. AP-181
Fix Linux issues.

Also added texture to be drawn when missing resource.
Get testing to work on Windows. AP-181
Merge branch 'AP-35' into AP-181

Conflicts:
	client/src/Game.cpp
	client/src/ICoreSystem.h
	client/src/Platform_Windows/CoreSystemWindows.cpp
	client/src/Platform_Windows/CoreSystemWindows.h
	client/src/Platform_Windows/GraphicsWindows.cpp
Merge current branches.

Conflicts:
	client/resources/resources.txt
	client/src/CMakeLists.txt
	client/src/Game.cpp
	client/src/ICoreSystem.cpp
	client/src/ICoreSystem.h
	client/src/Platform_Linux/CoreSystemLinux.cpp
	client/src/Platform_Linux/CoreSystemLinux.h
	client/src/Platform_Windows/CoreSystemWindows.cpp
	client/src/Platform_Windows/CoreSystemWindows.h