Feature/test for trim validation

I've added a test for trim to show that it doesn't currently work the same as CodeIgniter does.

I believe this also shows where the `return $_POST;` lines came from in @a0788a9dee82909265f776996f9f636cbfaf450f as that fixes the issue, but isn't really a suitable solution.

Is this the expected functionality? Should I just put trim around everything I insert/update?