moved RecursiveManager into its own module
moved RecursiveManager into its own module

i'm about to start splitting the Location stuff out of the reporters
app, and both apps have recursive models (Group and Location), so i'm
extracing this in advance.

peterayeni/rapidsms,catalpainternational/rapidsms,unicefuganda/edtrac,catalpainternational/rapidsms,peterayeni/rapidsms,ken-muturi/rapidsms,unicefuganda/edtrac,ehealthafrica-ci/rapidsms,ken-muturi/rapidsms,catalpainternational/rapidsms,eHealthAfrica/rapidsms,lsgunth/rapidsms,ehealthafrica-ci/rapidsms,lsgunth/rapidsms,dimagi/rapidsms,unicefuganda/edtrac,peterayeni/rapidsms,peterayeni/rapidsms,lsgunth/rapidsms,dimagi/rapidsms,ken-muturi/rapidsms,caktus/rapidsms,eHealthAfrica/rapidsms,catalpainternational/rapidsms,caktus/rapidsms,lsgunth/rapidsms,caktus/rapidsms,ehealthafrica-ci/rapidsms,eHealthAfrica/rapidsms