"San Luis II" - Bug fixes

This release fixes several issues:

• #75 (Email ALL hosts when submitting a show)
• #77 (Refactor all mail to just use notifications) - though ironically, some notifications will need to be refactored back to Mail just because of how Laravel works!
• #80 (Set "Reply-To" address to scheduling@ for scheduling emails)
• #81 (Enable cache busting)
• #85 (Add button to join screen to cancel the invitation entirely)
• #86 (Enforce length and profanity rules on show creation) - thanks to JP for finding this bug!
• #87 (Only list current term shows in the DJ roster)
• #89 (Don't show tracks in all shows which have an order of 0)

Additionally, a couple other issues are addressed which don't have official tracking numbers:

• Did some updates to validation; thanks to Rosemary for letting me know of validation issues. 0.7.1 should allow most fields to submit and validate within a second of last input, and should automatically allow access to the "Next" button when validation passes.
• JP wins for breaking the show creation screen, so that is now fixed.
• Rosemary also wins for getting a few creative expletives through the profanity filter; these are now blocked.

As always, thanks to everyone giving this round of Beta 2 a test!