Optimizations.
Optimizations.

- Removed unused "IE_VERSION";
- ++i is faster on IE 8-;
- faster clamp (inline if > Math.max/min on IE8- | jsperf.com);
- very fast matrixMultiply() (expanded calculations);
-
huip/excanvas,GerHobbelt/excanvas,huip/excanvas,thinkerchan/excanvas,thinkerchan/excanvas