Update bqplot viewer for bqplot 0.13.x

The 0.13.1 release of bqplot is out and while I think it preserves bqplot's functionality the package has been broken up into a few pieces. Of particular note here is that the GL markers are now in a seprate package.

Start by locating the bqplot viewer and checking its integration against bqplot 0.13.1, with special attention to GL markers now provided separately. Done means the viewer works with bqplot 0.13.x and its split marker package; the issue names no tests or files, so identify the relevant validation while tracing the integration.

Written by the indexing model from the issue text.