Tests presence of the xhr-response in the worker
Refactors encodeFloat and flex args
Refactors font matrix operations
Merge pull request #2454 from yurydelendik/worker-xhr-response

Tests presence of the xhr-response in the worker
Merge pull request #2505 from yurydelendik/refactor-cff-float

Refactors encodeFloat, font matrix and flex args
WIP - lots of subtle bugs