Merge branch 'Graphics' of https://github.com/DComm2013Network/CutThePower into Graphics
added mask layer function for fog of war
Merge branch 'Graphics' of https://github.com/DComm2013Network/CutThePower into Graphics

Conflicts:
	src/main.cpp
some codes for fog of war, not working atm..

Commented mask_render in src/main.cpp for now.
Uncommenting it will put a black mask over the surface.
Have trouble with implementing vision around a character.