Add preliminary streaming code for testing

 - Add some temporary streaming code using FFmpeg.  FFmpeg itself is not
   very ideal for streaming; lack of direct control of the sockets and
   no framedrop handling means that FFmpeg is definitely not something
   you want to use without wrapper code.  I'd prefer writing my own
   network framework in this particular case just because you give away
   so much control of the network interface.  Wasted an entire day
   trying to go through FFmpeg issues.

   There's just no way FFmpeg should be used for real streaming (at
   least without being patched or submitting some sort of patch, but I'm
   sort of feeling "meh" on that idea)

   I had to end up writing multiple threads just to handle both
   connecting and writing, because av_interleaved_write_frame blocks
   every call, stalling the main encoder thread, and thus also stalling
   draw signals.

 - Add some temporary user interface for streaming settings.  This is
   just temporary for the time being.  It's in the outputs section of
   the basic-mode settings

 - Make it so that dynamic arrays do not free all their data when the
   size just happens to be reduced to 0.  This prevents constant
   reallocation when an array keeps going from 1 item to 0 items.  Also,
   it was bad to become dependent upon that functionality.  You must now
   always explicitly call "free" on it to ensure the data is free, and
   that's how it should be.  Implicit functionality can lead to
   confusion and maintainability issues.