api: remove reserved NAL enums and C++ style comments from public header

--HG--
extra : rebase_source : 85f3089367c11655b4e23c8a2dc6232a6d4934ed
api: remove hungarian prefixes from x265_nal members

These particular prefixes came from x264 originally

--HG--
extra : rebase_source : 08130599663661b31deeb7bf6771c55c1d7a3027
api: remove old suffix and prefix from C symbols in comment, reflow

--HG--
extra : rebase_source : ba9cb99c569329d13c66fd519f3f5ce8931c535c
api: make x265_encoder_get_stats() somewhat future proof

By passing in the size of x265_stats as the user application knows about the
encoder can know not to try to set new fields that were added to the end of
x265_stats.  This requires some discipline on our part to only append to the
structure and to always check the size for any new fields we might add.

--HG--
extra : rebase_source : c56f65c702978bf47b256528b503dd62602696dd
api: nit

--HG--
extra : rebase_source : d8766641126dc98b6005076c7b489c4cc5906591
encoder: simplify size variables

--HG--
extra : rebase_source : e7aa509f91511410311d264067830e04308f7e2b
api: cleanup x265_param orderings, add full comments
common: validate --subme value
common: nit
cli: fix warning in CLI help
api: enable b-pyramid by default

The only reason for it to be disabled is if the decoder/use case prevented it
api: fix typos and improve chroma qp offset descriptions
api: enable weightp by default, disable for ultrafast
asm: code for transpose4x4 routine
asm: code for transpose_8x8 routine
asm: code for transpose_16x16 routine
TComYuv::copyToPicLuma, blockcopy_pp asm integration
TComYuv::copyPartToPartChroma, blockcopy_pp asm integration
csp support for blockcopy_ps
TComYuv::copyPartToPartChroma, blockcopy_ps asm integration