Multiple Changes...

* Needed to change route for Venues::venueCreateStart()
* Made necessary changes regarding route changes
* Added more checks and balances regarding routes, valid venue names and return codes
* Created 'VENUE_LABEL' constant instead of using Venues::getVenueLabel. Might switch this back
* Added new 'Create Venue' link to the nav bar
* Added a couple default values to the 'links' table creation schema