huge purge now that things work

includes refactor for to keep case list display settings separate from calcs
also make sorting work, using `headers.custom_sort = [[<int>, <asc|desc>]]`
clean up previous commit
Merge branch 'master' into purge

Conflicts:
	bihar/calculations/mortality.py
fix imports/whitespace
Merge pull request #69 from dimagi/purge

Purge