Add per window GL context for Cocoa libobs-opengl implementation

This fixes some problems with multiple swap chains (e.g. flickering
between the render views)
Release IOSurface only after it is no longer in use (e.g. by a texture)
Implement encoder usage with outputs

 - Make it so that encoders can be assigned to outputs.  If an encoder
   is destroyed, it will automatically remove itself from that output.
   I specifically didn't want to do reference counting because it leaves
   too much potential for unchecked references and it just felt like it
   would be more trouble than it's worth.

 - Add a 'flags' value to the output definition structure.  This lets
   the output specify if it uses video/audio, and whether the output is
   meant to be used with OBS encoders or not.

 - Remove boilerplate code for outputs.  This makes it easier to program
   outputs.  The boilerplate code involved before was mostly just
   involving connecting to the audio/video data streams directly in each
   output plugin.

   Instead of doing that, simply add plugin callback functions for
   receiving video/audio (either encoded or non-encoded, whichever it's
   set to use), and then call obs_output_begin_data_capture and
   obs_output_end_data_capture to automatically handle setting up
   connections to raw or encoded video/audio streams for the plugin.

 - Remove 'active' function from output callbacks, as it's no longer
   really needed now that the libobs output context automatically knows
   when the output is active or not.

 - Make it so that an encoder cannot be destroyed until all data
   connections to the encoder have been removed.

 - Change the 'start' and 'stop' functions in the encoder interface to
   just an 'initialize' callback, which initializes the encoder.

 - Make it so that the encoder must be initialized first before the data
   stream can be started.  The reason why initialization was separated
   from starting the encoder stream was because we need to be able to
   check that the settings used with the encoder *can* be used first.

   This problem was especially annoying if you had both video/audio
   encoding.  Before, you'd have to check the return value from
   obs_encoder_start, and if that second encoder fails, then you
   basically had to stop the first encoder again, making for
   unnecessary boilerplate code whenever starting up two encoders.
Add dummy GL texture flag & direct object access

 - Add dummy GL texture support to allow libobs texture references to be
   created for GL without

 - Add a texture_getobj function to allow the retrieval of the
   context-specific object, such as the D3D texture pointer, or the
   OpenGL texture object handle.

 - Also cleaned up the export stuff.  I realized it was all totally
   superfluous.  Kind of a dumb moment, but nice to clean it up
   regardless.
Minor fix to GL texture cleanup

Don't clear any data if it's a dummy texture.
Fix CMakeLists.txt for each project (my fault)
Improve serializer and add array serializer

The serializer code is meant to be used as a means of reading/writing
data from any arbitrary type of input/output.

The array output serializer makes it so we can stream data to a dynamic
array on the fly.
Add librtmp to obs-outputs

Note that this is a somewhat heavily modified custom version of librtmp.
I modified all the platform specific code that we were using for the
OBS1 to make it platform-independent.

I don't really like the code in this library, but it works well enough,
so I can't really fault anyone for it.  It's just very..  unclean.  Even
for a C library, quite unclean.  Some parts are also a little less safe
than I'd prefer as well.
Add preliminary FLV/RTMP output (incomplete)

 - obs-outputs module:  Add preliminary code to send out data, and add
   an FLV muxer.  This time we don't really need to build the packets
   ourselves, we can just use the FLV muxer and send it directly to
   RTMP_Write and it should automatically parse the entire stream for us
   without us having to do much manual code at all.  We'll see how it
   goes.

 - libobs:  Add AVC NAL packet parsing code

 - libobs/media-io:  Add quick helper functions for audio/video to get
   the width/height/fps/samplerate/etc rather than having to query the
   info structures each time.

 - libobs (obs-output.c):  Change 'connect' signal to 'start' and 'stop'
   signals.  'start' now specifies an error code rather than whether it
   simply failed, that way the client can actually know *why* a failure
   occurred.  Added those error codes to obs-defs.h.

 - libobs:  Add a few functions to duplicate/free encoder packets
obs-outputs module: Use the correct deps variable
Add missing project directives
Error on implicit declaration
Fixup libobs-opengl CMakeLists
Add a new install function to install targets into the datadir structure

This is mainly intended to be used for preloaded/injected DLLs, which
don't belong into the libdir or plugindir.
Disable strict-aliasing to avoid a bunch of possible problems
Add config.h generation and wrapper header, currently only for OBS_VERSION
Remove hard dependency on PulseAudio
Merge pull request #52 from BtbN/pfix

Several CMake fixes and enhancements
obs-output module: Fill out more functions

 - Add start/stop code to obs-output module

 - Use a circular buffer for the buffered encoder packets instead of a
   dynamic array

 - Add pthreads.lib as a dependency to obs-output module on windows in
   visual studio project files

 - Fix an windows export bug for avc parsing functions on windows.
   Also, rename those functions to be more consistent with each other.

 - Make outputs use a single function for encoded data rather than
   multiple functions

 - Add the ability to make 'text' properties be passworded
Fix bug where outputs wouldn't start up properly