Upgrade Bokeh to 0.12.10

[baderas]

Bokeh restructures its package(s)/package hierarchy every now and then.
The last working version is 0.12.6.
0.12.9 and 0.12.10 do not work anymore, see #10.
The only thing that must be done is probably fixing the imports.

[koppor]

Thank you for the update. The roadmap to 1.0.0 doesn't contain many items, but "Migrate BokehJS codebase to TypeScript" worries me a bit.

Regarding the concrete case:

Deprecated bokeh.charts support removed

The bokeh.charts module, which was simply a compatibility shim to load the separate bkcharts package, has been removed. Additionally, Bokeh itself no longer lists bkcharts as a dependency. In order to continue using bkcharts code, the bkcharts package must be installed separately.

Source: https://bokeh.pydata.org/en/0.12.10/docs/releases/0.12.9.html#deprecated-bokeh-charts-support-removed