TINYGL: Maths Code Refactoring

This pull request represents the completion of the first deliverable of my Google Summer of Code project.
The PR contains the c++ style math refactored code.
This code mantains the same level of performance of the original version (even though sometimes it also run  faster).
If you have any questions or doubts please ask.
That would be a massive refactoring for the whole library, it's not just maths code (and in fact this is not even maths code but zgl.h)