Server overhaul BEP

Hi,

Some may have noticed the giant PR-in-progress to change what Bokeh server is. I’ve written up some notes about it here in case people are interested or have feedback:

https://github.com/bokeh/bokeh/wiki/BEP-5:-New-Document-API-and-document-driven-server

This changes bokeh-server dramatically; it changes bokeh.io and bokeh.document.Document in ways that might affect people a little bit. It does not change bokeh.models, bokeh.plotting, etc. much at all.

This is still very ‘alpha’, but for the most part the examples that aren’t based on the old server should be working.

We want to land the PR on master soon and start working in smaller PR increments on the remaining loose ends.

Code review / questions / comments welcome. This is a lot of churn but we think it adds significant power while also simplifying the codebase and the API.

Thanks,

Havoc