Add TestClient with POSTing ability.
Add test for tip.json view.
Make changes to the tip.json tempalate to be altered by JS on change of donation amount.
Change JS to update the total amount given.
Restructure testing. Move client out, reinstate unicode_literals to testing/__init__.py
Point to the new testing module.
Fix ``get_number_of_backers``
Merge pull request #513 from alexcouper/25_update_total

25 update total (predominantly "Add test client")