demux_mkv: remove ancient codec mapping leftovers

All of this is basically due to how MPlayer's codecs.conf worked. It
had a demuxer-interface based an AVI, using FourCCs and data structures
found in AVI. FourCCs were used to map streams to decoders. For codecs
not supported by AVI, "MPlayer internal" FourCCs were made up.

codec_tags.c is there to bridge demuxers written against the old API to
the mpv one. By now, only demux_mkv.c needs this (because demux_mkv is
the only serious demuxer left - preferably, we should use libavformat
for mkv too, but I can't see this happening any time soon, because
libavformat _still_ doesn't support segment linking). But the codec
tables are full of weird stuff automatically extracted from the old
codecs.conf tables. Most of it isn't needed for mkv.

Remove all custom tags, readd those used by demux_mkv.c internally
(see vinfo and mkv_audio_tag tables). The rest is handled by the
tables provided by libavformat, which includes AVI and QT tags.
player: simplify and fix ordered chapter EOF handling

Ordered chapter EOF was handled as special-case of ending the last
segment. This broke --kee-open, because it set AT_END_OF_FILE in an
"inconvenient" place (after checking for --keep-open, and before the
code that exits playback if EOF is reached).

We don't actually need to handle the last segment specially. Instead, we
remain in the same segment if it ends. The normal playback logic will
recognize EOF, because the end of the segment "cuts off" the file.

Now timeline_set_from_time() never "fails", and we can remove the old
segment EOF handling code in mp_seek().
win32: add screen offset when handling overlarge windows

MS Windows doesn't allow windows larger than the screen, so we include
a hack to make the window smaller. This hack recenters the window (what
else would it do?).

It didn't account for the virtual offset of the current screen, and it
was reported that it forces the window to the first screen.

Should fix #1292.
build: don't install some files if only libmpv is built

encoding-profiles.conf can be used by libmpv, but it won't load it
from this path by default, so exclude it as well.

Fixes #1293.
TOOLS/lua: add script that pauses playback when minimizing the window

Uses functionality that was added a month ago for exactly this purpose.

Fixes #1237.
lua: add a function that formats Lua values as strings

Yep, Lua is so crappy that the stdlib doesn't provide anything like
this.

Repurposes the undocumented mp.format_table() function and moves it to
mp.utils.
vo_opengl: disable fancy-downscaling for anamorphic video

Includes some arbitrary minor refactoring.
vo_opengl: enable fancy-downscaling by default for opengl-hq
player: reset frame step counter on seeks

I suppose this wasn't done in order to keep the frame step counter
active even in the next file, but actually it was reset anyway.
command: avoid returning invalid FPS values

It's possible that fps is sometimes 0 in case it's unset.
player: don't ignore relative seeks by 0 seconds

I don't know why this done; most likely it had no real reason.

Remove it because it breaks "refresh seeks" to the same position.
(Although the refresh seeks mpv sometimes does were fine.)
manpage: minor fixes

Also update the Lua example. The "pause" event was declared deprecated,
so the example should use the newer API.
vo_wayland: Add "multimedia" keyboard key bindings.

libxkbcommon keysyms are the same as X11 keysyms (sans prefix),
so I simply copied the missing subsection from x11_common.c.

Signed-off-by: Sergey Kvachonok <ravenexp@gmail.com>
Signed-off-by: wm4 <wm4@nowhere>
manpage: lua: fix example

Oops.
manpage: rename input.conf supersection

By now, input.conf is actually just a small part of input handling.
Rename the section to something else ("command interface" was the
first reasonable thing that came to mind).

Also fix a minor typo further down.
demux_playlist: don't ignore last line in m3u

If EOF is reached after reading a line, the EOF flag is set. This was a
problem for the m3u code, which checked for EOF _after_ reading a line,
which will discard the last line read.

Also fix a typo in an unrelated part of the file.
ao/wasapi: get rid of WAVEFMT union

It only confused the issue. Replace it's functionality with
waveformat_copy function where needed.
ao/wasapi: make sure that < 16-bit pcm never happens

it just sucks. noone should have to listen to that.
ao/format: add af_fmt_is_float
ao/wasapi: don't assume 32-bits == float

This was based on old WAVEFORMATEX restrictions
http://msdn.microsoft.com/en-us/library/windows/hardware/ff538799%28v=vs.85%29.aspx

With the new WAVEFORMATEXTENSIBLE, this is no longer a problem. and we
can have s32 or float32 so we need to actually check / set these correctly.

fixes #1287