Merge pull request #2 from adlnet/master

to_xapi now returns a tuple
Added PRT event tracking
Minor buffer change, PRT fix
Updated video tracking to use new merge function

also changed suspended to completed on stop_video
Merge pull request #3 from adlnet/master

Minor change to how objects are merged
Merge remote-tracking branch 'origin/prt'

Conflicts:
	xapi-bridge/converter.py