DATAJPA-353 - Fixed mapping file locations detected by CPSPUPP to conform to the JPA spec.

Adjusted scanForMappingFileLocations(…) in ClasspathScanningPersistenceUnitPostProcessor to resolve the paths to class-path loadable paths. Updated test cases accordingly. Added test case and required resources to verify that mapping files with recursive wildcard pattern can be found from multiple locations in class path.

Original pull request: #24.