Merge commit 'a83c0da5'

* commit 'a83c0da5':
  avconv: make -t insert trim/atrim filters.

The filter insertion code is merged but disabled as it is buggy.
For example it fails in various ways when used with -s with some files.
Also the trimming is arguably less accurate than the default without
filters in some cases.
These issues should be fixed before auto inserting the filters,
until then the user can explicitly add a trim/atrim filter when one is
wanted.

Conflicts:
	Changelog
	ffmpeg.c
	ffmpeg_filter.c
	tests/ref/fate/bethsoft-vid
	tests/ref/lavf/aiff
	tests/ref/lavf/asf
	tests/ref/lavf/au
	tests/ref/lavf/avi
	tests/ref/lavf/dpx
	tests/ref/lavf/ffm
	tests/ref/lavf/gxf
	tests/ref/lavf/jpg
	tests/ref/lavf/mkv
	tests/ref/lavf/mmf
	tests/ref/lavf/mov
	tests/ref/lavf/mpg
	tests/ref/lavf/nut
	tests/ref/lavf/ogg
	tests/ref/lavf/pcx
	tests/ref/lavf/png
	tests/ref/lavf/rm
	tests/ref/lavf/ts
	tests/ref/lavf/voc
	tests/ref/lavf/voc_s16
	tests/ref/lavf/wav

Merged-by: Michael Niedermayer <michaelni@gmx.at>