Setting a value that is shown through a helper doesn't work

[eviltrout]

I have created a fiddle to show how this works:

http://jsfiddle.net/Qpkz5/325/

Essentially it seems that if you update a value that has a helper, the update does not work. In the example, if you remove the "dummy" helper the update works.

[wagenet]

@eviltrout Your helper is not binding aware. See #615 for a possible solution.