* Add user-defined category-label colors
Fixes https://github.com/chanzuckerberg/cellxgene/issues/1152
As described in https://github.com/chanzuckerberg/cellxgene/issues/1307
* Respond to feedback from @bkmartinjr in nodejs
* Respond to feedback from @bkmartinjr in python
* Add tests to the server module
* Autoformat python, run linter
* Make colors_get error handling specific
* Respond to feedback from @bkmartinjr
* Respond to feedback from @bkmartinjr
* Fix whitespace
* Fix python lint errrors
* Update documentation
* Add --disable-user-colors option to launch and cxgtool.py
* Fix python formatting
* Rename '--disable-user-colors' to '--disable-custom-colors'
* Improve diffexp for tiledb
- The rows from the A and B sets are gathered and processed at the same time. In this
way the matrix is only accessed once instead of twice for each tile.
- There is now a single thread queue that gets shared between all callers of the diffexp.
This will slow down work if diffexp gets too busy.
- There is a target_workunit amount of work given to each thread. Previously the
workunit was (rows selected * width of tile), which could be small. Now multiple
column tiles can be combined into one workunit. If the target is too small then
thread and other overheads may reduce performance. If target_workunit is too large
then the size of the gathered sub matrix may take up too much memory.
- add configuration parameters (max_workers, cpu_multiplier, and target_workunit)
