Use C externs for obs-module.h

This allows inter-sharing of functions such as obs_module_text among
both C and C++ files
Rename linux-xshm module to linux-capture
Combine linux-xcomposite and linux-capture (xshm)
linux-capture: Rename pos_* vars to render_*

the pos_x and pos_y variables were somewhat deceptive, because they were
not actually the poition of the cursor.  They represented the position
of the cursor's bitmap on the screen, not the position of the cursor.
linux-capture: Add x/y cursor position vars
linux-capture: Add cursor capture to xcomposite
No need to subtract window position from translated coordinates
Merge pull request #262 from computerquip/master

No need to subtract window position from translated coordinates
Move timestamp smooth threshold to media-io
Perform timestamp smoothing in media-io as well

Doing timestamp smoothing in obs-source.c is good because timestamps can
typically operate on a different timebase, however, obs-source.c can
also change that time base dynamically (such as with async video and
unexpected timestamp jumps), so in order to ensure that audio is
seamless in the output as well, perform timestamp smoothing in
audio-io.c as well just as an extra precautionary measure.
Add function to get info on a specific source to pulse wrapper
Use source instead of server info to get format for recording in pulse input

When setting up the capture, the plugin will now query pulse for the default
format of the specific source instead of the server.
This is useful if a source has different settings than what the defaults are
for the server, e.g. when the source is an output with 5.1 surround sound
and the microphone input is mono while the server defaults to stereo sound.
Simplify logging in pulse input

Use a macro to prefix debugging messages instead of prepending manually.
Small coding style fixes in pulse input
Log average latency in pulse input

This adds another statistics counter to the pulse plugin in order
to print the average latency reported by pulse when the source is
destroyed.