screenshot: enable taking screenshots with subtitles

This will take unscaled snapshots of the video with subs included.

By default nothing changes. You have to trigger this behavior with the
slave command "screenshot 0 2", where the "2" indicates this screenshot
mode.

CAVEATS: this creates a new libass renderer on every screenshot.
Depending how libass handles font loading and initialization, this
could be quite slow. The libass cache will be cleared on every
screenshot as well. Expect that using this screenshot command can
introduce noticeable jitter during playback.
Also note that libass keeps a minor amount of state per subtitle
event, that will cause conflicts if an event is processed by multiple
renderer instances. libass detects when this happens, but rendering
will look different. (The problem is with subtitle collision detection,
see get_render_priv() and callers in ass_render.c.)
screenshot: fix dependency on sizeof(AVFrame)

The AVFrame data structure may be extended at the end in new
binary-compatible libavcodec versions. Therefore applications should
not depend on the size of the structure. But screenshot.c declared an
"AVFrame pic;" on stack. Change the code to allocate an AVFrame with
avcodec_alloc_frame() instead. The frame is now stored in struct
screenshot_ctx (rather than reallocated each time).
subassconvert: handle unquoted attributes in subrip font tags

Previously, mplayer didn't convert tags like <font color=#00FF00>. But
such subtitles exist in the wild, and should be handled.
subassconvert: make subrip attribute parsing more robust

Add general code to separate the HTML-like attribute=value syntax used
in srt font tags into attribute and value parts. This simplifies some
of the parsing code, makes detection of malformed input more robust,
and allows warning about unrecognized attributes.
stream_ffmpeg: fix broken line from 30afc64532ff61

Commit 30afc64532ff61 ("stream_ffmpeg: switch to libavformat avio
API") somehow contained a nonsense line which broke the control()
function. Fix. Also add avformat_network_init() to central libav
initialization code to avoid warnings.
ad_ffmpeg: switch to avcodec_decode_audio4()

Switch libavcodec audio decoding from avcodec_decode_audio3() to
avcodec_decode_audio4(). Instead of decoding directly to the output
buffer, the data is now copied from the libavcodec output packet,
adding an extra memory copy (optimizing this would require some
interface changes).

After libavcodec added avcodec_decode_audio4() earlier, it dropped
support for splitting large audio packets into output chunks of size
AVCODEC_MAX_AUDIO_FRAME_SIZE or less. This caused a regression with
the previous API: audio files with huge packets could fail to decode,
as libavcodec refused to write into the AVCODEC_MAX_AUDIO_FRAME_SIZE
buffer provided by mplayer2. This occurrend mainly with some lossless
audio formats. This commit restores support for those files; there are
now no fixed limits on packet size.
configure: --enable-debug: don't change other compiler flags

The --enable-debug and --enable-profile options set their own compiler
flags, completely different from normal flag selection. These flags
sucked; especially '-W' (an obsolete alias for '-Wextra') generated a
huge number of irrelevant warnings. Change configure to only add "-g"
or similar to the flags that would be used otherwise.
core: uninitialize VO and AO when no track plays

Uninitialize video and audio outputs when switching to a file without
a corresponding track (audio-only file / file with no sound), or when
entering --idle mode. Switching track choice to "off" during playback
already did this.

It could be useful to have a mode where the video window stays open
even when no video plays, but implementing that properly would require
more than just leaving the window on screen like the code did before
this commit.
core: change initial sync with --delay, video stream switch

Make A/V sync at the start of playback with nonzero --delay behave the
same way as it does when seeking to the beginning later, meaning video
plays from the start and audio is truncated or padded with silence to
match timing. This was already the default behavior in case the
streams in the file started at different times, but not if the
mismatch was due to --delay. Trigger similar audio synchronization
when switching to a new video stream. Previously, switching a video
stream on after playing for some time in audio-only mode was buggy and
caused initial desync equal to the duration of prior audio-only
playback.
win32: core: wake up more often to poll for input

MSWindows does not have properly working support for detecting events
on file descriptors. As a result the current mplayer2 code does not
support waking up when new input events occur. Make the central
playloop wake up more often to poll for events; otherwise response
would be a lot laggier than on better operating systems during pause
or other cases where the process would not otherwise wake up.
vo_corevideo: use soft tabs (4 spaces)
vo_corevideo: use cocoa_common to display the window

Change vo_corevideo to use cocoa_common to create and manage the
window. This doesn't affect external OSX GUIs, since they don't use
vo_corevideo window management, but only read the image data from the
shared buffer.
vo_corevideo: restructure this video output

Restructure this video output to be similar to vo_gl, even if simpler
and less feature complete (for example it's still missing EOSD
support). Ideally, it should act as a decent fallback in the case
where something breaks in the OSX support of vo_gl.

Here's a summary of what changed:

 * Remove the shared buffer code since it wasn't using any function
   from the CoreVideo API. Moreover, its presence in vo_corevideo was
   forcing the non-GUI related code to perform more image copies than
   necessary. Equivalent shared-buffer functionality will be added in
   a separate new VO in the next commit (this means OSX GUIs will need
   to specify a different VO).

 * Clean up the code to conform a bit more to the mplayer2
   conventions. Enforce 80 column wrapping, use a private struct for
   file variables, use the new libvo api.

 * Add OSD rendering using OpenGL instead of writing directly on the
   video image data.

 * Simplify the logic for the rendering function when dealing with
   panscan.

 * Add VOCTRL_REDRAW_FRAME support.

 * Add colormatrix support by using the built-in API provided by
   CoreVideo.
vo_sharedbuffer: add this video output

This OSX video output is replaces the previous shared_buffer mode of
vo_corevideo. It manages a shared buffer and a Cocoa distributed
object to communicate with GUIs.

Splitting this code into a separate VO allows to get rid of harmful
code coupling, performance inefficiencies (useless image memory
copies) and ugly code (big if-else conditionals).
OSX, input: implement wakeup in response to Cocoa events

Add code to wake up the select() call in input.c when an OSX event is
available and a Cocoa OpenGL backend is initialized.

Fixes the slow response to input or other events in Cocoa-based VOs
during long select() sleeps (e.g., when mplayer2 is paused) introduced
by commit 7040968.
cocoa_common, gl_common: add OSX specific getProcAddress

Run dlopen on the OpenGL dynamic library instead of on the binary.
This should prevent crashes due to function conflicts when X11/lGL is
linked.

Remove mutual exclusion of the X11 and Cocoa backends.
Makefile: fix OSX compilation with --disable-corevideo

cocoa_common.m (enabled under COCOA) depends on osx_common.c, but the
latter was erroneously only enabled under COREVIDEO.
configure: OSX: check for X11 header conflict with corevideo

Check that headers from ApplicationServices and X11 do not conflict
before enabling X11 support on OSX. Both headers would be included in
vo_corevideo.m (through QuartzCore/QuartzCore.h and gl_common.h). The
conflict exists on versions of Mac OSX prior to 10.7, where
ApplicationServices includes the deprecated QuickDraw framework,
resulting in a clash on the Cursor type definition.
cocoa_common: fix problems with alt-tab window changes

Fix alt tabbing to another window in the same workspace. The player
window stayed on top because of a missing call to orderBack:.

Fix alt tabbing to the player window from a different workspace. The
window didn't get activated. Turns out that you must call
makeKeyAndOrderFront: before setLevel: or setPresentationOptions: or
the window will not properly ask for focus.
Merge remote-tracking branch 'origin/master'

Conflicts:
	command.c
	libao2/ao_alsa.c
	libao2/ao_dsound.c
	libao2/ao_pulse.c
	libao2/audio_out.h
	mixer.c
	mixer.h
	mplayer.c

Replace my mixer changes with uau's implementation, which is based on
my code.