Merge pull request #565 from bcipolli/rename_total_logins

HOTFIX: renaming misnamed 'total_logins' to 'count'
cannot take max on None; add max_none function
another bugfix redo
Merge branch 'max_none' of github.com:bcipolli/ka-lite into friendly_admin

Conflicts:
	kalite/coachreports/views.py
	kalite/utils/general.py