Add rate limiting for sync service downloading

A background sync operation can make the system unusable as every single network operation will basically never finish until the SyncAdapter is done downloading.
Fix PlaylistAdapter not picking up deleted cache after first pass
Only show notification after entire playlist sync is done
#142 Add pull to refresh to all views
Remove refresh button from everywhere
Remove pointless intermediate messages
Merge branch 'RateL' of https://github.com/daneren2005/Subsonic
Merge branch 'PullRefresh' of https://github.com/daneren2005/Subsonic