kept all properties, etc.. internal just so that they can be found so we don't have to register them.
Updates unit test to ensure the plugin manager is init'd properly with the 'false' override. Ensures that the base
db test also initializes the plugin manager properly.
Adding a MediaTypeMapper similar to the ContentTypeMapper, but type specific.
The PetaPoco IMapper implementation is removed as its no longer needed.
Updating a few unit tests, as the Where clause is now correctly formatted.
Adding unit tests for the new ExpressionHelper and MappingResolver classes.
