give ESQuerySet a __repr__
give ESQuerySet a __repr__

to make debugging nicer

qedsoftware/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq