param: clip bframe bias range as x264 does
encoder: set m_totalFrameThreads at the same time as param->frameNumThreads
nal: greatly simplify NAL header generation, do not use TComOutputBitstream

This saves a malloc/free and a great deal of needless overhead
nal: msvc and its integer conversion warnings
frameencoder: remove obsolete check
TComDataCU: nits
compress: remove floating point math to avoid needing to use EMMS
weight: ensure weight table is initialized on failure, simplify weightAnalyse()
compress: nit comment spacing
frameencoder: re-use a single bitstream object for all NAL and SEI

This saves on malloc/free/realloc/memcpy calls.