vo_opengl: avoid texture arrays for compatibility with Intel low quality crap

Commit a0b43a1 changed textures to an array, because additional
per-texture information was needed and managing this as array is more
elegant. This broke playback on Windows with Intel drivers (window
shows green video, even though subtitles/OSD work correctly). So change
it back to make it work again.

Affected driver: Intel(R) HD Graphics 3000 9.17.10.2932
Merge branch 'master' into low_quality_intel_crap

Conflicts:
	video/out/gl_video_shaders.glsl
	video/out/vo_opengl.c
configure: rename --enable/disable-libquvi to --enable/disable-libquvi4

--disable-libquvi creates the impression that it disables libquvi 0.9
as well. It doesn't, because it refers to libquvi 0.4, and 0.4 and 0.9
are practically completely different libraries. Make this more explicit
by renaming the switch to include the "4" version number.
ao_jack: increase buffer size, always round up buffer size

This should help with github issue #128, which reported stuttering
distorted sound with 6 channel audio, but not with 2 channels.
ao_jack: allow more control about channel layouts
core: make network options available even if old net code is disabled

Preparation for removing the old network code.
Remove internal network support

This commit removes the "old" networking code in favor of libavformat's
code.

The code was still used for mp_http, udp, ftp, cddb. http has been
mapped to libavformat's http support since approximately 6 months ago.
udp and ftp have support in ffmpeg (though ftp was added only last
month). cddb support is removed with this commit - it's probably not
important and rarely used if at all, so we don't care about it.
manpage: fix section headings
stream: re-add accidentally removed seek call

This was under CONFIG_NETWORKING, so in theory it should have been save
to remove. But actually this disables forward skipping when reading
from a pipe. (Still a questionable feature, because it doesn't behave
well with libavformat - but it was not supposed to be changed.)
stream: remove weird STREAMTYPE_STREAM special handling

This was an old leftover from an earlier cleanup (which happened in
2003), and which used "special" stuff for streams that could be only
forward-seeked.

Also, don't add mode flags to s->flags; they're supposed to be in
s->mode instead.
Remove some leftovers from network removal

stream_vstream.c in particular was actually dependent on the network
code, and didn't compile anymore.

Cleanup the protocol list in mpv.rst, and add some missing ones
supported by libavformat to stream_lavf.c.
stream: don't treat position 0 specially

Seeking to position 0 meant to try reconnecting with some streams,
actually just the internal http implementation. This has been removed,
so we don't need the special handling anymore.

This means we don't have to be stuck in a retry loop if the stream
doesn't even support reconnect.
configure: prune some more crap

All of the removed lines are hopefully useless and didn't do anything.
configure: simplify arch macros
osdep: remove unused mmap compatibility hacks

Not sure how this worked. Only af_export.c and tvi_v4l2.c were
using mmap, but they didn't include osdep/mmap.h or mmap_anon.h. In
any case, we trust that the target system is sufficiently POSIX
compliant if mmap is actually defined (as checked by configure).
stream: unbreak streams with large sector sizes (stream_cdda)

Commit 7b16d4b changed some stream implementations to check the buffer
size passed to them. This made stream_cdda stop working, because the
default buffer size is smaller than the CDIO frame size. So pass the
sector size instead of the (arbitrary) default buffer size.
Fix building with --disable-libass

Obscure corner case, but in theory we support this.
configure: link with -lrt

In order to use clock_gettime() (which we need for use with
pthread_cond_timedwait()), most glibc versions need to link with -lrt.
configure: fix previous commit

This doesn't help if -pthread is omitted. (Apparently, glibc 2.17, on
which I tested the previous commit, doesn't require -lpthread in order
to use pthreads either.)
stream_radio: fix build

This was accidentally broken with 37c5c11 and has been nroken for
5 months.

Does anyone (want to) use this at all?