Introduced JpaSort for sorting by JPA meta-model attribute paths. Introduced JpaMetaModelPathBuilder that can be used to ease the construction of Jpa meta-model attribute paths by the provided static factory method. Added new testing scenario (MailMessage and MailSender) to avoid to mess up the existing sample classes. Enabled static JPA meta-model generation in pom.xml.
Enhanced Querydsl to generate appropriate left joins when sorting by nested (singular) association properties. Converted XML configuration for QueryDslRepositorySupportIntegrationTests into JavaConfig.
Original pull request: #54.
692b2382bf