* added cubic interpolation and catmull-rom interpolation support to const_math and the vector class
 * interpolation should/can only work with floating point types
 * added fused-multiply-add (fma) support to const_math, const_math_select (selects between simple (a*b)+c and __builtin_fma) and the vector class
 * added support for popcount, clz, ctz, ffs and parity operations to the vector class (implemented via the __builtin_* functions that are luckily already constexpr)
 * return of the prefix header (seems to work correctly again in xcode 6.0)