Make the "required" param on args optional
Add the ability to specify default param values in register_json_route
Include defaults checks in Request unit tests
Test setting default param value via register_json_route
Change defaults to lowercase
Remove required false attribute from test_default_param and test_default_param_is_overriden
Spelling fix overriden -> overridden
Add test for optional param not set.
Set the $request var to an array.
Merge branch 'develop' into optional-required-arg

Conflicts:
	tests/test-json-server.php
Merge pull request #728 from WP-API/optional-required-arg

Make the "required" param on args optional