Respect the user-specified existing templates during JPAQuery.clone()

Fixes #1071 and resolves #1072 

Thinking out loud here, what should reflect the outcome.

method | behavior 
----------|---------
`clone()` | copies all state over(including custom templates)
`clone(em)` | attaches with the specific templates for that EntityManager
`clone(em, templates)` | attaches with respect to the specified custom templates