clarifying autoredraw usage in getting-started

This was very confusing to me & I don't think the getting started docs make this clear enough.  I thought that 2-way databinding existed and 

1. creating a view that reads values from a controller (with `m.prop` properties) and
2. using `m.module` to initialize the connection

was all that was required to make the data flow both directions.  The getting started docs didn't make clear that this is not the case.

per discussion here:
https://groups.google.com/forum/#!topic/mithriljs/1v7rpJG73SU