Minor changes to help with first time indexing

I had trouble when I was first indexing.  It would seem to complete without saying anything.  So, I added a "-v" option to allow some verbosity to be able to tell what the heck was going on.

Figured out that the issue was that ACCEPTED_FORMATS used to be defined in shiva/config/project.py but that got removed in aa76a0a however the indexer.py still examines it and would never match in is_track() so nothing would be indexed.  Decided to warn the user to update the configuration similar to the warning just above for MEDIA_DIRS.

I can clean/change either of these if required.