Overhaul library, rename to cgmath

Moved the old source code temporarily to src-old. This will be removed once the functionality has been transferred over into the new system.

The new design is based on algebraic principles. Thanks goes to sebcrozet and his nalgebra library for providing the inspiration for the algebraic traits: https://github.com/sebcrozet/nalgebra
Close repository

This project can now be found at https://github.com/bjz/cgmath-rs