Improve Renderer documentation
Switch to new enum style
Add documentation and checks to SceneGraph
Add ability to specify left/right bottom/top limits to orthographic projection matrix
Improve Camera by adding world_to_screen()/screen_to_world() and some fix/additions here and there
Update Lua Camera bindings
Update OsWindow metrics when necessary
Replace ComponentList with separated fixed-size array of components
Simplify JSONParser and fix a critical bug preventing chained json data access
Add very basic .unit compiler
Register .unit compiler into BundleCompiler and fix compiled resource names
Add support to Unit to PackageResource and ResourcePackage
m_begin is not necessary anymore. Yeah.
Fix wrong size when writing out Unit resource data
Fix wrong function name
Fix spacing between error message and resource hash
Fix missing GL_CHECK
Add destory_unit() and fix link_sound()
Merge branch 'world' of https://github.com/taylor001/crown into world

Conflicts:
	engine/CMakeLists.txt
	engine/Unit.h
	engine/compilers/package/PackageCompiler.cpp
	engine/compilers/package/PackageCompiler.h
	engine/resource/PackageResource.h
	engine/resource/ResourcePackage.h
	engine/resource/ResourceRegistry.cpp