[CXF-5561] Introducing constants

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1567911 13f79535-47bb-0310-9956-ffa450edef68
[CXF-5430]: Added initial support for OData 2.0 query language. Covered most of advanced use cases (JPA)

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1567912 13f79535-47bb-0310-9956-ffa450edef68