Fix: test testOfflineCachingAttributeInOffline fails when run alone, but succeeded in a context.
RFWebResponse cache managed object was refactored with a main goal to make future cache migrations easier. All object fields except indexed were hidden under transformable property.
Migration from outdated WebService cache was added.
WebService cache migration: fix for cache tests.
WebService cache migration: small improvement in migration procedure.
Merge pull request #359 from ptiz/master

Initial version of a new WebService cache and its migration