OfflineGuides: Don't restart sync upon open

We want to let the sync do its thing rather than cancelling and
restarting it if you open the OfflineGuidesActivity.
Change progress color if not syncing

Just a little touch to make it more clear that the items aren't syncing
at the moment.
Update UI on offline guide removal
Fix notification display issues

We must reset the notification objects so subsequent syncs adhere to the
same rules as the initial sync.
Guide view: Disable menu items if offline

They won't work and will only cause problems/confusion.