Added comments outlining how we might support double entry of both groups
Groups that are both sharing and reporting double entered in options. g__ now designates reporting groups, sg__ for sharing groups.
Merge branch 'caselistmixin-refactor' into double-enter-both-groups
Fixed syntax error
Fixed a bug with populating the filter field on page reload
Merge branch 'caselistmixin-refactor' into double-enter-both-groups

Conflicts:
	corehq/apps/reports/filters/users.py
limit case sharing groups to the CaseListReport
Move share group limitations up into the EMWFw/alldata
Renamed a for_group to for_reporting_group to better reflect the new distinction
Removed resolved comments
Merge pull request #4220 from dimagi/double-enter-both-groups

Double enter groups that are both reporting and sharing groups in the EMWFOptions for CaseListMixin reports.