demux_disc: bluray: fix stream language (2)

Commit 50e131b43ed happened to make it work for DVD (because the higher
bits of the ID are masked in the DVD case), but failed for Bluray. This
probably fixes it, although I don't have a sample to multiple streams to
confirm it really does it right.

CC: @mpv-player/stable
vo_vdpau: don't try to create surfaces of size 0

At least on kwin, we decide to proceed without waiting for the window
being mapped (due to the frame exts hack, see commit 8c002b79). But that
leaves us with a window size of 0x0, which causes VdpOutputSurfaceCreate
to fail. This prints some warnings, although vo_vdpau recovers later and
this has no other bad consequences.

Do the following things to deal with this:
- set the "known" window size to the suggested window size before the
  window is even created
- allow calling XGetGeometry on the window even if the window is not
  mapped yet (this should work just fine)
- make the output surface minimum size 1x1

Strictly speaking, only one of these would be required to make the
warning disappear, but they're all valid changes and increase robustness
and correctness. At no point we use a window size of 0x0 as magic value
for "unset" or unknown size, so keeping it unset has no purpose anyway.

CC: @mpv-player/stable
sub: round scaled subtitles

Simple fix for issue #1137.

Since all sub-bitmaps are packed on a larger texture, there's still a
"fall off" on the border due to the linear scaling. This could be
fixed by constraining each sub-bitmap to its own texture, or by
clamping on the shader level, but I don't care for now.
audio/filter: don't wipe full filter chain if adding a filter fails

There's no need for that, and in fact makes it more likely that it
recovers normally.
audio: refactor some aspects of filter chain setup

There's no real reason why audio_init_filter() should exist. Just use
af_init or af_reinit directly. (We lose a useless message; the same
information is printed in a quite close place with more details.)

Requires less code, and the way the filter chain is marked as having
failed to initialize allows just switching off audio instead of
crashing if trying to insert a volume filter in mixer.c fails, and
recreating the old filter chain fails too.
command: move setting playback speed to a separate function
audio/filter: allow removing filters by label

Although the "af" command already could do this, it seems it's better
to introduce a lower level mechanism for now. This avoids some messy
issues, since that code would recursive call reinit_audio_chain().

To be used by the next commit.
audio: enable pitch correction by default when playing fast

Apparently this is what users want. When playing with normal speed,
nothing is done. When playing slower than normal, resampling is used
instead, because scaletempo (which does the pitch correction) adds
too many artifacts.
player: don't print audio/video init failure message twice

The messages "Audio: no audio" and "Video: no video" could be printed
twice each if initializing them failed. Prevent his silliness.

CC: @mpv-player/stable
manpage: redocument audio delay key bindings

Fixes #1131.
CC: @mpv-player/stable