Horribly munge up the CABAC tables to allow deduplication of some data.
Saves 256 bytes of L1d cache in non-RD, 512 bytes in RD.
Add asm versions of bypass and terminal; save L1i cache by re-using putbyte code.
Further optimize encode_decision.
All 3 primary CABAC functions fit in under 256 bytes of code total on x86_64.