Fix floating point exceptions from dividing by CLOCKS_PER_SEC

Use omp time
Wired up EntityManager to World, refactored rendering loop to take SDL initialization out into worldsim.cpp, so RenderSystem only focuses on manipulating the pixel texture.
Wired up EntityManager and RenderSystem - RenderSystem now manages to draw blue "lake" entities to the screen.
WaterSystem now randomly modifies the waterLevel of every water in the world - just as a test, to see if RenderSystem successfully renders the correct water levels.
Boosted simulation dimensions to 800x600 for shits and giggles. Testing with 10,000 "lakes" now with cilk_for rendering. Manages to max out 8 cores...
Merge branch 'develop' into graphics

Shader still WIP; Hardcoded pixel RGBs for now so no waterlevel coloring

Conflicts:
	Systems/RenderSystem.cpp
	Systems/RenderSystem.h
	worldsim.cpp