Some fixes and additions to scrobbler

Fix possible crashes in scrobbler.py
Add ability to disable sending watched calls on seek and when resuming playback, this can cut down on wait times from the API, for example playing a movie and seeking to the end in 10 minute skips to scrobble it.  This would mainly benefit those who usually have long response times from trakt.tv
Close progress dialog if results from trakt or xbmc are invalid, otherwise dialog stays on screen with no way to remove it