Code review comment for lp://staging/~gary/juju-gui/fixDeltaFromChangeEdgeCase

Reviewers: mp+185053_code.launchpad.net,

Message:
Please take a look.

Description:
optimize and fix databinding.deltaFromChange

This is a grabbag of three small changes. The biggest change is that I
did some optimizations of databinding.deltaFromChange and fixed an edge
case (with test). I also optimized _setupDependencies for that edge
case, added some documentation about bindings (so I could refer to it
myself), and optimized the bind/_bind pair a bit by removing redundant
calls to code that iterates over all bindings (they are now done once in
bind, rather than once per viewlet in _bind).

https://code.launchpad.net/~gary/juju-gui/fixDeltaFromChangeEdgeCase/+merge/185053

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/13348056/

Affected files (+71, -29 lines):
   A [revision details]
   M app/views/databinding.js
   M test/test_databinding.js