DATAJPA-500 - Verify that sorting of Embeddables with Querydsl works.

Added test case to verify that sorting by nested embedded attributes with querydsl expressions works. Previously a CCE was thrown due to changes in org.springframework.data.jpa.repository.support.Querydsl.

Please ignore commit 58651f7 - it is just a temporary fix as master currently doesn't compile due to a refactoring in SD Commons.

Original pull request: #70.