When /bin/sh isn't bash, the previous line always appears to succeed,
and modinfo's output is not redirected, because it actually runs
modinfo in the background (which always succeeds) then opens and closes
/dev/null without doing anything to it. This causes us to always think
that the v4l2loopback module is installed, even when it isn't.

Using modinfo dumps all the output into the terminal instead redirect
all output to dev/null.

This functionality can now be handled automatically because locale can
now be freed seaparately from obs_module_unload with
obs_module_free_locale, which is called automatically when the module is
being freed.

Replaced by obs_get_version() API

This patch adds a plugin to capture video data from v4l2 devices under linux.

We use the default format to avoid any resampling by pulse audio,
since obs will probably resample anyways if necessary.

- first try at implementing a pulse audio input plugin,
  it is currently completely untested.

- added license headers to source files

Moved the screen grabbing and texture generation to the
_tick function in order to keep _render fast.
Migrated xshm video source to the new plugin api.

added linux test module with first implementation of a screengrabber using the xshm extension for x11