Wintermute transparent surface refactoring/optimization

Done some refactoring to the blending functions, after profiling the code I verified that functions weren't inlined with the previous method so I created three functions that execute different types of blending.

I also moved the kA/R/G/BIndex constants in the cpp files and scoped them locally to improve readability and removed the branched versions on the individual blending functions as they were making the code run slower.