Add DummyContactsResource.handlers.update
Add validation for Contact.subscriptions
Add DummyContactsResource update_extras and update_subscription handlers
Add DummyContactsResource .search handler
Add DummyContactsResource .get_by_key handler
Merge branch 'develop' into feature/issue-106-add-missing-contacts-resource-methods
Merge branch 'develop' into feature/issue-106-add-missing-contacts-resource-methods
Merge branch 'feature/issue-106-add-missing-contacts-resource-methods' into develop