* changed win32 implementation to QueryPerformaceTimer system function
* refactored system utils code
* proper tests for time utils and update event creation in application
* should fix issue #134
- fixed model loading code
- added simple model viewer (model_test) in src/graphics/opengl/test
- added system time stamp code
- split the code in app/system modules to separate headers
- added debug messages in model loading
- minor fixes in OpenGL engine
Piotr Dziwinski