gl_video: add RGB10_A2 FBO format

Maybe this can be the default in the future, but I'm not sure yet.
vo_opengl: don't enable PBOs with opengl-hq

The speed advantages are marginal (at least with the way it's currently
used), and it might actually be slower on some drivers, like Mesa.
audio/filter: rename af_force.c to af_format.c

The filter itself was already renamed earlier - but rename the file too.
af_force: minor simplifications
af_force: set format early for better debug output

Set the input/output format in filter init. This doesn't change anything
functionally, but it makes the forced format show up in the filter chain
init verbose output (which sometimes prints the filter chain before all
filters have been configured).
audio/filter: remove useless af_info fields

Drop the author and comment fields. They were completely unused - not
even printed in verbose mode, just dead weight.

Also use designated initializers and drop redundant flags.
video/out: remove useless info struct and redundant fields

The author and comment fields were printed only in -v mode.
video/filter: remove useless vf_info fields

This time I didn't bother to move the contents of the author field to
the file headers. "git log" is your friend.
audio/out: remove useless info struct and redundant fields
manpage: use the new name for af_force in one place
cocoa: fix race condition with input context creation

This seems to be a problem only in OS X 10.9. I guess they improved the
general speed of the Cocoa startup and suddenly mpv core takes more time
than the Cocoa thread to initialize.

Fixes #285

(hopefully!)
cocoa: fix opening quarantined files on 10.9 with the bundle

It looks like on Mavericks the Finder is passing different arguments to mpv
depending on whether the opened file is quarantined or not.

Fixes #285
m_config: cosmetics: make code less verbose
m_config: don't allow aliasing with string options

Minor simplification. String options are now not allowed to use the
same variable/field anymore. (Also affects other "dynamic" options
which require memory allocation.)
m_config: slightly simplify dynamic option initialization

We can assume memcpy is enough, because the source should be from
static data. (It wouldn't work if the data could contain pointers
back into itself.)
m_config: refactor initialization, reduce amount of malloc'ed strings

Allocate strings only if needed (when we have to prefix sub-options).
Prepare for storing m_config_options in an array instead of a list.
m_config: store m_config_options in an array instead of a list

Might reduce memory overhead, and is also less annoying.

Since pointers to m_config_options are kept around, this assumes
they're added only during initialization. Otherwise you'd get
dangling pointers.
m_config: minor simplification

I think in this case, having a separate function is confusing.
m_config: don't require dragging along parent in initialization

Instead, track the opstruct explicitly. It turns out we don't need the
parent at all. Also, add something rudimentary to track the default
values.
options: fix bogus entry

This didn't make sense and caused issues with the following commit: if
it's an option with a data pointer, it should be writable.