DATAJPA-631 - ResourceLoader improvements in ClasspathScanningPersistenceUnitPostProcessor.

A custom ResourceLoader configured on ClasspathScanningPersistenceUnitPostProcessor is now propagated to the ClassPathScanningCandidateComponentProvider used for looking up entity classes. We also forward the configured environment so that profile annotations are evaluated as well.

Related issue: DATACMNS-591.
DATAJPA-632 - Fix SimpleJpaQueryUnit test after cleanups in Spring Data Commons.

We now use a JpaQueryMethod instance rather than a mock as isPageQuery() cannot be mocked anymore as it has been made final.

Related issue: DATACMNS-601.
DATAJPA-634 - Switched to HTTPS for repository declarations.
DATAJPA-629 - Allow SpEL template expressions in combination with parameter expressions in @Query.

Previously SpEL template expressions like #{#entityName} could not be used in conjunction with parameter expressions in @Query because the SpEL template parser tried to evaluate the dynamic parameter expressions as well. We now mask the parameters prior to evaluating the SpEL template expression.

Original pull request: #122.
DATAJPA-523 - Make Specifications implement Serializable.

Specifications now implements Serializable to be able to transfer them across systems boundaries. Introduced special Serializable Specification types for composed and negated Specifications.

Note that currently only Hibernate and EclipseLink expression structures implement Serializable - OpenJPA's don't.

Original pull request: #86.
DATAJPA-606 - Improve handling of empty arrays and collections in query parameters.

Prepare issue branch.
DATAJPA-606 - Improve handling of empty arrays and collections in query parameters.

Introduced potentiallyConvertEmptyCollection method to PersistenceProvider for provider specific handling of empty collections. Special handling is performed for Hibernate and EclipseLink. Conversion is performed in ParameterMetadata.prepare(..). Renamed ParameterMetadataProvider.accessor to bindableParameterValues.

This is an version of the original pr: #123 adjusted to the 1.7.x branch.

Original pull request: #124.