If the current timecode can't be parsed, the plugin falls back
to last knonw timecode to at least have something. The code
that does this already existed but the last_timecode was just
never set.
* The Debug category was moved to a lazy_static!.
This allowed for a couple of methods, to be implemented
directly against the State struct since the debug category
was their only dependency from MccParse.
* Log the Caps/Format change
The ones for gstreamer and glib are left there to avoid importing
the macros from weird paths, since the bindings are not yet ready
for this modules system
