Add get_appropriate_subclass to XFormInstance, dispatched on doc_type
Add get_appropriate_subclass to XFormInstance, dispatched on doc_type

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