Merge pull request #55 from BtbN/ffmpeg

Add compatiblity for some older ffmpeg versions
Added GLX_NV_copy_image extension, updated tools
Merge pull request #56 from jp9000/new-gl-loader

Added GLX_NV_copy_image extension, updated tools
More extensions, less bugs
Merge pull request #57 from jp9000/new-gl-loader

More extensions, less bugs
Add window capture

Now that we have the priorties window in we can finally be able to
select windows for capture source such as window capture.  Only took
about an hour or two to write.

Also, fixed some depednency issues on winmm.lib with obs-outputs
Use atomics for allocation counter

I was getting cases where the CPU cache was causing issues with the
allocation counter, for the longest time I thought I was doing something
wrong, but when the allocation counter went below 0, I realized it was
because I didn't use atomics for incrementing/decrementing the
allocation counter variable.  The allocation counter now always should
have the correct value.
Add comments to config-file.h

Someone got rather confused over what the "default" functions did, so
hopefully this clears it up a bit.
Fix graphics device export header

Caused D3D11 library to fail on load.  Don't know how I didn't see this
sooner.
Add old new pa code
Update
Use new settings interface