wtv: Seek by sector properly

Use an helper function to seek by sector to avoid possible mistakes
due shifting by WTV_SECTOR_BITS a 32bit integer.

Contrary to common intuition, a 32 bit integer left shifted
by a 64 bit integer does not promote the 32 bit integer to
64 bit before shifting.
avformat/wtv: rename to wtv_common

This helps git matchup files on merges correctly

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  wtv: Seek by sector properly

Conflicts:
	libavformat/wtvdec.c

See: a0d13d84a928110b0e99ea16d17fd758fcbde35f
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avformat/wtvdec: drop SHIFT_SECTOR_BITS() macro

it just wraps around a bitwise shift, and makes the code harder to read

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
doc/developer: Add a policy item about updating the MAINTAINERs file

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
HEVC Encoding via libx265

Obviously relies on Anton's HEVC patch set.
Revert "lavc/hevc: mark decoder as experimental"

This reverts commit f2dd45d06c606c41bcbf227ffc47e1ac0ce37d65.