get rid of POST routes where it makes sense

[brummett]

For things like the order forms and entity-edit forms, it might make more sense for the form to be implemented as an object. The caller (in the GET route) would then wait for the form to be "submitted" via a Deferred().

The form submission callback could then pull the right data out of the form and return it to the caller as an object. The callback would then preventDefault() on the submission event.

This puts the form interpretation in the same module as the other form behaviors