Vector2/3/4 + Quaternion Optimizations

- variable reuse (less mem, faster attribution - http://jsperf.com/pro-var-reuse);
- "undefined" replaced by "void(0)", since is slight faster, value safe and uses less chars (http://jsperf.com/typeof-vs-undefined-check/21);
- .roundToZero(), using bitwise operator;
- using *-1 to negate properties (better minification, http://jsperf.com/fast-negate-numeric-property);
- multiply is faster than divide (http://jsperf.com/multiply-vs-divide/3) ex: /2 to *0.5 and /4 to *0.25;
- minor optimizations.