Adding collection handling for identity return

Adds the ability for the 'Return(identity)' overload to cope with
collections.
Adding code review changes
Binary Expressions (== and !=) handled in Return

Return statements now handle == and != for null elements.
Update to the location of the message const

And a quick word change.
Merge pull request #28 from cskardon/issue-27

(Issue 27) Binary expressions in the return statement.
Merge pull request #25 from cskardon/issue-24

Adding collection handling for identity return