Semantic Issue: Magnitude of floating-point constant too large

Hi

First, thank you very much for sharing YHAnimatedCircleView and for the blog with the detailed information. Very helpful. 

I was getting compiler warnings in Xcode 4.5.2  

Semantic Issue: Magnitude of floating-point constant too large for type 'float'; maximum is 1.7014116E+38

This pull request just sets ANIMATION_REPEAT to HUGE_VALF to get rid of the compiler warnings.

Thanks Again.

Very Helpful.