Refactoring of the guy demo. Added keyboard control and cool background.

The guy on the screen can be controlled via keyboard:
arrowkeys move him back and forth 
space make him jump

Open point: for some reason glfw keyboard control is very strange. When another button pressed during repeat event, it breaks this repeat event. For example, if you move right and want to make a jump, space-key breaks GLFW_REPEAT key action. Do not know why =(