RenderHelper enhancements

Added javadoc for every method in renderHelper class.
RenderHelper now stores renderPos and blockPos independently.
New methods: setRenderPos(int x, int y, int z)
             setBlockPos(int x, int y, int z) for autobrightness
renderPos's use intVector3D instead of Vector3D from minecraft sound engine.
setPos(x,y,z) remains same (sets both renderPos blockPos)
Alowed method chaining for renderHelper. (every method returns this)
Fixed:
    Brightness
    Color
Added:
    setBrightness(int brightness)
    clearBrightness() = setBrighness(-1)
    setColor(float red, float green, float blue)
    clearColor() = setColor(1,1,1)