Be more strict when resolving, actually use mapping between URI prefix and entity.

- needed for future hooks that rely on the URI.
Repackage EntityResolver, better in the rest package, it's a RESTful bridge really.
Repackage files, missing 'mpu' package.
Refactor due to repackage.
Missed repackage of data file for test.
Allow passing in command line args to maven in build script (e.g. build.sh -PIntTest).
Create test data builder for User objects, refactor.
Add tests for and minor refactoring of EntityResolver.
Mark field as private.
Simplify tests, reduce redundant statements.
Better test entityUriMismatch() scenario, using actual entity.