Refactoring of OpenType/TrueType font construction

We are using bytesToString and then using stringToArray just to concatenate multiple chunks of the Open Type file. The patch refactors code to build the file directly in the continuous Uint8Array. Also removing stringToArray since the file builder can accept the strings (not just arrays).
is it actually worth allocating segCount2? its only used once. (the old code could have used it twice (rangeShift calc) but didn't.