Optimized Lexer_getObj 2x faster
utils.js optimization of isFOO methods
evaluator.js minor optimizations
Optimized CanvasGraphics_executeOperatorList 66% faster
canvas.js minor optimizations
Optimized genericComposeSMask

Declaring the composition and backgdrop functions outside of genericComposeSMask
is more efficient.
Minor refactoring of EvaluatorPreprocessor_read
Merge pull request #4895 from p01/Small_optimizations_1

Small optimizations 1