Adding ByteArray.readFile for html5
Adding ByteArray.readFile for html5

This will always be blocking, and an async api version elsewhere will
be added (for both native+js)

mrcdk/snow,snowkit/snow,mrcdk/snow,underscorediscovery/snow,underscorediscovery/snow,mrcdk/snow,mrcdk/snow,mrcdk/snow,snowkit/snow,underscorediscovery/snow,snowkit/snow,mrcdk/snow