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
You're right, we need `qqplot` like functionality (less boilerplate for very common use cases).
So let's stick with them, and see how we'll have to adapt or add new ones.