Cellxgene

Changes
* Add cluster occupancy - when coloring by categorical metadata, stacked barchart shows proportional breakdown of other categorical fields. E.g. color by gender, evaluate gender makeup of each cluster
* Add Docker support

Changes:
- Add a typeahead, with fuzzy string search, on the Selected Gene text box
- Improve error handling and detection of ScanPy data containing NaN or Infinite values.
- Add `--nan-to-num` command line parameter to convert NaN/Infinite to finite floating point values.
- Minor improvements to startup speed

Breaking changes:
- Added `--host` command line option, replacing `--listen-all`. The equivalent of `--listen-all` can now be accomplished with `--host 0.0.0.0`

Changes

* Update to latest version of sklearn

Changes
* Allow downcasting of float64 to float32

Changes
* Fixes images on pypi

Fixes issue 457

Changes
* Improved handling of numerical and boolean data types