vd_ffmpeg: disable codec direct rendering and slices by default

This caused failures when doing single threaded decoding in some cases.
It's unknown what exactly the reasons are for these failures, but
direct rendering is probably worthless anyway.

Disable slices by default as well, just to be sure not to invoke broken
code paths. Multithreading disables these too.

The old behavior can be restored by passing the -dr1 -slices command
line options. (-dr1 is left undocumented intentionally.)

Multithreaded decoding worked fine, because vd_ffmpeg.c automatically
disables direct rendering in this case.
Port several python scripts to Perl

file2string.pl and vdpau_functions.pl are direct ports.
matroska.py was reimplemented as the Parse::Matroska module in CPAN,
and matroska.pl was made a client of Parse::Matroska.
A copy of Parse::Matroska is included in TOOLS/lib, and matroska.pl
looks there first when trying to load the module.

osxbundle.py was not ported since I have no means to verify it.
Python is always available on OSX though, so there is no harm in
removing the check for it on configure.
demux_mkv: don't crash on tracks with unknown audio codecs

Demuxers can't remove streams anymore after adding them, so the
free_sh_audio() call caused a crash.
demux_mkv: TTA support

Code from libavformat's demuxer.

Merged by wm4. It looks like the byte stream writer API is private in
newer ffmpeg, so use the macros from <libavutil/intreadwrite.h>
instead.

It's not really known how to correctly set the field that is used by
the decoder to calculate the length of the last frame. The original
patch used:

    put_le32(&b, (demuxer->movi_end - demuxer->movi_start) * sh_a->samplerate);

This doesn't seem to be correct. Write 0 instead. This is also
incorrect, but better than writing an essentially random value.
ao_coreaudio: signal per-application mixer support

The CoreAudio AO's AOCONTROL_GET_VOLUME/AOCONTROL_SET_VOLUME operate on the
AUHAL's volume, and every application has it's AUHAL with a separate volume.

Additionally CoreAudios's mixer seems to be better. As much as I tried to, I
couldn't get it to clip sounds.
cocoa_common: honor the `--geometry` option
vo_opengl: add manual sRGB companding to not artifact when dithering

Patch by nand. Modified not to use macros in the GLSL, and also remove
the checks for framebuffer presence. (Disabling ICC if no sRGB
framebuffer is available was probably a bug.)
manpage: vo_opengl: document that srgb subopt changes gamma
Replace fast_memcpy() uses

fast_memcpy, defined in fastmemcpy.h, used to be mplayer's "optimized"
memcpy. It has been removed from this fork, and fast_memcpy has been
reduced to an alias for memcpy. Replace all remaining uses of the
fast_memcpy macro alias.
vo_opengl: disable extended downscaling by default

To simplify implementation, the same filter kernel was used for both
directions, even when the scaling factors were different. It turns
out that people actually did this, and that the resulting rendering
errors were rather visible. Disable this feature by default, as
fixing it would require structural changes, and it's a useless anyway.
example.conf: remove some useless options, add some useful ones
vo_xv: don't call vo_xv_get_eq() on every frame

This was done to query the colorspace for sub/OSD rendering. A
single vo_xv_get_eq() call probably requires a dozens of round-trips
(depending what xlib actually does). This likely wasn't a real problem,
but it might be better to be paranoid about this.
vo_opengl: fix srgb for subtitles

Based on a patch by nand. This is needed, because sRGB mode changes the
video over-all gamma. This has to be done for subtitles as well.
The final srgb_compand() call in the OSD shader compensates for the fact
that in ed8fad729d04 framebuffer use was replaced with doing sRGB
conversion manually by srgb_compand().

This only affects subtitles rendered with libass. Nothing is changed for
RGB subs.

Also change the USE_ flags for OSD shaders to USE_OSD_ to make the
difference between video and OSD rendering more apparent.
vo_opengl: fix compatibility with OpenGL 2.1

The srgb_compand() function passes bvec to mix(), which is apparently
not available on GL 2.1 / GLSL 1.20:

0:0(0): error: no matching function for call to `mix(vec3, vec3, bvec3)'
0:0(0): error: candidates are: float mix(float, float, float)
0:0(0): error:                 vec2 mix(vec2, vec2, vec2)
0:0(0): error:                 vec3 mix(vec3, vec3, vec3)
0:0(0): error:                 vec4 mix(vec4, vec4, vec4)
0:0(0): error:                 vec2 mix(vec2, vec2, float)
0:0(0): error:                 vec3 mix(vec3, vec3, float)
0:0(0): error:                 vec4 mix(vec4, vec4, float)

Also add back disabling color management on older GL, as the
srgb_compand() function is needed for that.
mpv_identify: stop using \n; fix property name handling

Dashes are not valid in shell variable names. This changes them to
underscores.
Rename directories, move files (step 1 of 2) (does not compile)

Tis drops the silly lib prefixes, and attempts to organize the tree in
a more logical way. Make the top-level directory less cluttered as
well.

Renames the following directories:
    libaf -> audio/filter
    libao2 -> audio/out
    libvo -> video/out
    libmpdemux -> demux

Split libmpcodecs:
    vf* -> video/filter
    vd*, dec_video.* -> video/decode
    mp_image*, img_format*, ... -> video/
    ad*, dec_audio.* -> audio/decode

libaf/format.* is moved to audio/ - this is similar to how mp_image.*
is located in video/.

Move most top-level .c/.h files to core. (talloc.c/.h is left on top-
level, because it's external.) Park some of the more annoying files
in compat/. Some of these are relicts from the time mplayer used
ffmpeg internals.

sub/ is not split, because it's too much of a mess (subtitle code is
mixed with OSD display and rendering).

Maybe the organization of core is not ideal: it mixes playback core
(like mplayer.c) and utility helpers (like bstr.c/h). Should the need
arise, the playback core will be moved somewhere else, while core
contains all helper and common code.
Rename directories, move files (step 2 of 2)

Finish renaming directories and moving files. Adjust all include
statements to make the previous commit compile.

The two commits are separate, because git is bad at tracking renames
and content changes at the same time.

Also take this as an opportunity to remove the separation between
"common" and "mplayer" sources in the Makefile. ("common" used to be
shared between mplayer and mencoder.)
Add missing compat/libav.h includes

For avcodec_free_frame().
libav.h: increase compatibility by not including libavutil/version.h

libavutil/version.h was only recently split off from
libavutil/avutil.h, and that file includes version.h anyway.
mp_common.h: split parts into mp_talloc.h and compiler.h

Put MP_EXPAND_ARGS() in compiler.h, even though it's not compiler
dependent. Both mp_talloc.h and mp_common.h need it, while mp_common.h
includes mp_talloc.h. This is the least annoying solution.