clean up and memoize is_member_of and has_permission methods of CouchUser
clean up and memoize is_member_of and has_permission methods of CouchUser

SEL-Columbia/commcare-hq,dimagi/commcare-hq,gmimano/commcaretest,SEL-Columbia/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,gmimano/commcaretest,qedsoftware/commcare-hq,qedsoftware/commcare-hq,SEL-Columbia/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,puttarajubr/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,gmimano/commcaretest,puttarajubr/commcare-hq,qedsoftware/commcare-hq