DATAJPA-363 - Improved implementation of SimpleJpaRepository.delete(ID id).

Remove the additional call to exists(…) in favor of a null check, we'd have to trigger anyway in the case of and exists success. This will avoid triggering an additional query.
DATAJPA-148 - Remove qualification of sort reference for functions.

When applying Sort instances we now check for the presence of a ( which indicates a function to be executed.