adding cleanup of files
Implemented some changes from ryankevans/docker-sickbeard
Upstream Merge - branch 'master' of https://github.com/timhaak/docker-sickbeard

Conflicts:
	Dockerfile
Revert "fixes #1: existing Sick Beard database is overwritten when the container starts"

This reverts commit 8a820b7f18fa0e7e1fa09c6ea60fdc3f971f95ff.