Create and view performances

This feature turned out to be several:
*Create a performance
*View a performance
*View the date create and by whom
*Add multiple customers and multiple partners to a performance
*View all customers and partners associated with a performance
*View a list of all performances by customer

@amZotti, @MikeyMurph77 - please take a look
Almost.  The admin is the only one who can add customers, but anyone can add a contact.  Customers are organizations, and contacts are people.  So regular users can add contacts.