CompositeTexture: Fix include guard name
Shader: Fix leak in LoadFromStrings
Merge branch 'develop-0.1.x' into develop-0.2.0
internal/Graphics: Check for optional extensions
Utility: Check extensions after posting system info to log
internal/Graphics: Include header
gdk/Application: Add config loading
gdk/Application: Break main loop if window is closed
gdk/Application: Update config loading
gdk/engine: Tweak entry code and logging
internal/Graphics: Blank log line after checking optional extensions
gdk/Application: Updating log messages in various config methods
gdk/Application: Store which buffers to clear
gdk/Application: Private members -> protected
gdk/Application: Document _CreateDefaultConfig