Use `get_params` method added in #681.
Unskip test_json_update_user and use PUT method.
Use PUT method in test_update_user.
Cast the params as an array when merging.
Merge pull request #683 from WP-API/two-users-put

Wrap up PUT handling in Users Controller
Merge branch 'develop' into two-posts-routes
Correct name of /posts post_type parameter to type.

- Fix parameter name in route registration.
- Fix parameter name in WP_JSON_Posts_Controller::get_items().
- Minor clean-up to get_items request parameter handling.
- Correct parameter name in test_get_items_type_param() test.
Correct return types for WP_JSON_Controller::get_items().

Was removed in 0e54628adf953cee0e9c0be3c4b7ad503c6dbcd0 because it was not correct.
Move allowed query_vars logic out of get_items() into separate method.
Add context parameter to /posts/ route.
Remove unnecessary sanitization for request context
Register route to edit posts.
Comment out all json_post hooks until Media Controller is migrated to new style.
Fill-in logic for test_create_item
Add test for Location header in add or edit post response.
Fix missing second parameter for sticky post handling.
Comment out json_insert_post in update_item method.