CC-5709: Airtime Analyzer

* Better SIGTERM handling for airtime_analyzer
* Nuke the .identifier files saved by Airtime
CC-5709: Airtime Analyzer

* Bounce files with file extensions we don't support in MediaController
* Added translation stuff for Recent Uploads
CC-5709: Airtime Analyzer

* CC-5772: Recent Upload table times should be shown in local time
Merge branch 'cc-5709-airtime-analyzer' into cc-5709-airtime-analyzer-saas

Conflicts:
	airtime_mvc/locale/de_DE/LC_MESSAGES/airtime.po
	airtime_mvc/locale/es_ES/LC_MESSAGES/airtime.po
Merge branch 'cc-5709-airtime-analyzer-saas' of github.com:sourcefabric/Airtime into cc-5709-airtime-analyzer-saas