Implement subscription adapter. Add entry adapter and  test classes
finish subscription adapter and add two tests
- subscriptions over users and partnerships are supported
- before you read it: huge hack alert.
Update subscription.rb
add save functionality to subscriptions
change method name resource#object_uri to resource#absolute_uri,
resource#create_entiti_uri to resource#create_absolute_uri
and Resource#create_entity_uri to Resource#create_absolute_resource_uri
Merge branch 'subscr_adapter' into dev