Bokeh

- integrated bokeh on backend&frontend side (bbossy's changes)
- added example workbook
- started work on "simplification" layer for bokeh-scala (imho poorly documented, please give feedback here -> software design could probably be better... not 100% sure yet on which direction to take). Idea: simplify the 80% tasks/plots data analyst have to do in terms of plots/statistical analysis.
- added spark configurator workbook
I'll try to hack something this evening. I think we can use the Backbone notification system to do that.
So we can react on PlotContext changes on the server side by seeing the attached plots changing on the UI side.
I think I'll first merge the PR, so that the current features are ensured :-D

@see http://jsfiddle.net/bokeh/K8P4P/light/  [source.set data and source trigger change]