The dvbsub routines were originally designed as a mini lib with a
log callback (which from the looks of it in our case would always
be called and always assemble the string even with debug output
disabled). Some of these debug statements can probably be removed
or cleaned up some more.
Eases holding onto the information in gst plugins side queue of
DVBSubtitles, so we won't need to create yet another temporary struct
to keep the pts and page_time_out too.
And this really logically belongs at the toplevel information set anyway
and in that struct...
We want to allow queueing of raw region image data in the gst plugin side,
and keep the data around until we pop the item from the queue. So make
the callback handler responsible for memory cleanup, if one is installed.
