Merge with default
slicetype: remove x265_ prefix from internal functions

These were adapted from x264 functions, and the prefix was incorrectly preserved
slicetype: respect --bframes count when --b-adapt is 0

--b-adapt 0 --bframes 3  => IPBBBPBBBPBBB
--b-adapt 0 --bframes 4  => IPBBBBPBBBBPBBBB

This is a stop-gap feature until --b-adapt 1 and 2 are fully functional
Added tag 0.4 for changeset 2ba6ec553f21
Merge with stable