mpegvideo: drop support for real (non-emulated) edges

Several decoders disable those anyway and they are not measurably faster
on x86. They might be somewhat faster on other platforms due to missing
emu edge SIMD, but the gain is not large enough (and those decoders
relevant enough) to justify the added complexity.
vp8: drop support for real (non-emulated) edges

They are not measurably faster on x86, they might be somewhat faster on
other platforms due to missing emu edge SIMD, but the gain is not large
enough to justify the added complexity.
vp9: drop support for real (non-emulated) edges

They are not measurably faster on x86, they might be somewhat faster on
other platforms due to missing emu edge SIMD, but the gain is not large
enough to justify the added complexity.
FATE: add MSS2 tests
hevc: fix decoding of one PU wide files

For those the block size may be larger than the source linesize (if the
edges are not allocated).

Signed-off-by: Anton Khirnov <anton@khirnov.net>
mjpegdec: apply flipping after decoding, not before

This is simpler and removes a silly restriction on edges being present.
ac3tab.h: #include the correct headers
x86: avcodec: Add a bunch of missing #includes for av_cold
x86: hpeldsp: Add missing av_cold attribute to init function
ATRAC3+ decoder

Cleanup by Diego Biurrun.

Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>
flac muxer: add option to disable writing the global header

The global header is not explicitly required for playback, and
omitting it allows for simple concatenation.
lavfi: add framepack filter
fate: add framepack filter test
avfilter: add documentation for needs_writable
avfilter: add needs_writable field to the internal AVFilterPad structure
avfilter: fix leaks on error in ff_filter_frame
avutil: do not use avcodec header in frame.h