Add a unique validation to email addresses within the same account
fixed behavior of Unique validations when updating (vs. creating) objects
Adjust display models with multi-line output as List<string> instead of single preformatted string
added SelectLists for the definitions of the same type within a tank
Added test cases for all SelectList populations
Merge branch 'dev' into View
Finalize Definition page, only needs dropdown now. Added separate JS for show/hide logic so it doesn't crowd the markup.