Modifies aspect ratio comparison to allow for a tolerance.

Related to https://github.com/flavioarfaria/KenBurnsView/issues/2

This is still a problem for me. I debugged the MathUtils.haveSameAspectRatio method and found out that every time the exception is thrown the aspect ratios differ in 0.01 because of the previous truncation. 

I have modified the comparison operation to allow for a tolerance so it never returns false for aspect ratios that are practically equals.