Parse URL-encoded body with PUT requests

Also parses for PATCH requests, but it's unlikely those will ever be
sent as URL-encoded.
Use stripslashes_deep with magic quoted parameters
Add method to get merged set of parameters
Use correct constants for route methods

This ensures that POST, PUT and PATCH all work for editing, for example.
Use the server for running tests
Indicate that updating a user can take JSON
Register the user deletion endpoint
Ensure updating a user updates the correct user :)
Merge pull request #681 from WP-API/parse-put-parameters

Parse URL-encoded body with PUT requests
Merge pull request #682 from WP-API/two-end-to-end-users

End to end testing for users
Merge branch 'end-to-end-terms' of https://github.com/WP-API/WP-API into end-to-end-terms

Conflicts:
	plugin.php