Implement ordering for users
Respect order of order queries, and convert ' ' to implicit '+'

About the second point:
Werkzeug silently converts a '+' if finds in query values to a ' ',
meaning that if you query `GET /users?order=+id ` you end up with ' id'
in your `request.args`. So the helpers also accept ' ' as an implicit
'+', and tests verify that.
Adapt helper test to fail on ordering of order queries
Merge branch 'url-queries-space-and-order' into url-queries-tests

Conflicts:
	yelandur/test_helpers.py