Uses rAF to interrupt the operator list execution
Merge pull request #4763 from yurydelendik/canvas-rAF

Uses rAF to interrupt the operator list execution
Optimized stream.js 9.7x faster DecodeStream_ensureBuffer
Optimized function.js / 33% Faster PDFFunction_constructPostScriptFromIR
Optimized colorspace.js AlternateCS_getRgbBuffer