use std:: namespace for most cmath functions:

http://en.cppreference.com/w/cpp/header/cmath

(cpp standard says std:: should be used)

i did this because we use assimp for the spring engine. this engine uses streflop which replaces all math functions. with the std:: prefix these can be a lot easier search/replaced.

also removed an useless #ifdef in matrix4x4.inl + some whitespace