Load helpers from directory + fixed regex.

Hi!

I've started to use helpers a lot and got annoyed with adding them manually.

While implementing this, I've noticed that regex for controllers and views is slightly incorrect and in some cases can lead to a bug. There was an unescaped dot (which would match any character) while literal dot was expected. I've also added `$` to make sure the `.js` or `.coffee` is really an extension. Finally added `.coffee.md` extension, as it wouldn't match otherwise.

There is lot of repetition in this loading logic. Maybe we could refactor it a bit in a DRY manner?

:)