Renamed fog to haze.
Optimized the haze rendering: The haze color and alpha is now pre-mixed
to the color of the underlying polygon/rect. This saves us to make a
couple of hundred additional draw calls per frame on the render buffer.
disabled background scrolling temporarily.
Made color mixing for polygons and blitRect part of the render buffer
class.
Optimized renderSegment method.
Optimized onRender loop.
Improved renderSprite method.
Compiled another test build.