Fix memory leaks in stasis_channels and bridge_native_rtp

This patch fixes two memory leaks:
 * A memory leak in packing channels into a multi-channel blob payload when
   publishing dial messages. The multi-channel blob payload does not steal
   the references - this approach was chosen because it works well with the
   RAII_VAR macro. Unfortunately, this does mean that you actually have to use
   the RAII_VAR macro (or manually deref it yourself)
 * RTP instances returned as a result of one of the glue operations are ref
   counted and have to be de-ref'd appropriately. We now do that, as saying
   that we should do it and then not would be silly.




git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@391479 f38db490-d61c-443f-a65b-d21fe96a405b
Fix memory leak while loading modules, adding formats, and destroying endpoints

This patch fixes three memory leaks
 * When we load a module with the LOAD_PRIORITY flag, we remove its entry from
   the load order list. Unfortunately, we don't free the memory associated with
   entry in the list. This patch corrects that and properly frees the memory
   for the module in the list.

 * When adding a custom format (such as SILK or CELT), the routine for adding
   the format was leaking a reference. RAII_VAR cleans this up properly.

 * We now de-ref the channel_snapshot appropriately when an endpoint is
   disposed of
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Merged revisions 391489 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 391507 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@391521 f38db490-d61c-443f-a65b-d21fe96a405b