review pass on widgetmanager.js
quick review pass on javascript
review pass on Python-side of widgets

- remove variable signature complexity
- use a few more traitlets as appropriate
catch NotImplementedError, not NotImplemented

in _ipython_display_
Document _ipython_display_ in custom display logic
first review pass on widget tests
review pass on widget examples
Merge pull request #11 from minrk/widgets

Widget review