Adds Promise to the getOperatorList
Terminate getOperationList and getTextContent every 20 ms
Merge pull request #4770 from yurydelendik/promise-operationlist

Adds Promises to getOperatorList
Strict isEOF / ~22% faster on issue2813, from 16.5s to 13.5s
Fewer lookups in CanvasGraphics_constructPath
Removed several 'in' operators in canvas.js

This gives up to 6x speed improvement on these methods
Merge pull request #4817 from p01/graphic_optimizations_3

Graphic optimizations 3
Added some changes
Merge branch 'master' of https://github.com/mozilla/pdf.js into svgbackend
Converted operatorList to opTree
operatorlist => optree