bringing back srp js
make sure billing tests do not interfere with others

they are still broken though.
moving broken billing integration tests out of the way

They are currently using fake_braintree. I think this is not a good approach for integration tests. It's a fake - we should test against braintrees test api. However that requires getting an api key that we want to keep outside the repository. So these test can only run on travis if we manage to setup secret values in .travis.yml - which has been failing so far.

So for now i moved the broken billing integration tests to billing/test/broken to move on.
move engines into engines directory

Also renamed help to support so it's harder to confuse it with documentation
minor: our engines do not have a db directory