Only write current-level elements in write_connectivity().
Only write current-level elements in write_connectivity().

Now that all the elements are stored in the _local_elements std::set,
we have to handle iterating only over the current level manually.

balborian/libmesh,svallaghe/libmesh,balborian/libmesh,jwpeterson/libmesh,benkirk/libmesh,90jrong/libmesh,capitalaslash/libmesh,hrittich/libmesh,giorgiobornia/libmesh,friedmud/libmesh,friedmud/libmesh,friedmud/libmesh,svallaghe/libmesh,svallaghe/libmesh,jwpeterson/libmesh,giorgiobornia/libmesh,benkirk/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,hrittich/libmesh,BalticPinguin/libmesh,hrittich/libmesh,jwpeterson/libmesh,dschwen/libmesh,90jrong/libmesh,jwpeterson/libmesh,balborian/libmesh,benkirk/libmesh,friedmud/libmesh,friedmud/libmesh,libMesh/libmesh,90jrong/libmesh,libMesh/libmesh,roystgnr/libmesh,roystgnr/libmesh,BalticPinguin/libmesh,svallaghe/libmesh,giorgiobornia/libmesh,pbauman/libmesh,hrittich/libmesh,giorgiobornia/libmesh,balborian/libmesh,giorgiobornia/libmesh,roystgnr/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,vikramvgarg/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,balborian/libmesh,hrittich/libmesh,svallaghe/libmesh,benkirk/libmesh,jwpeterson/libmesh,dschwen/libmesh,roystgnr/libmesh,capitalaslash/libmesh,benkirk/libmesh,pbauman/libmesh,pbauman/libmesh,BalticPinguin/libmesh,hrittich/libmesh,BalticPinguin/libmesh,dschwen/libmesh,BalticPinguin/libmesh,libMesh/libmesh,vikramvgarg/libmesh,friedmud/libmesh,balborian/libmesh,roystgnr/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,benkirk/libmesh,hrittich/libmesh,90jrong/libmesh,libMesh/libmesh,dschwen/libmesh,BalticPinguin/libmesh,giorgiobornia/libmesh,svallaghe/libmesh,roystgnr/libmesh,vikramvgarg/libmesh,capitalaslash/libmesh,90jrong/libmesh,vikramvgarg/libmesh,capitalaslash/libmesh,friedmud/libmesh,pbauman/libmesh,vikramvgarg/libmesh,balborian/libmesh,libMesh/libmesh,svallaghe/libmesh,roystgnr/libmesh,friedmud/libmesh,90jrong/libmesh,dschwen/libmesh,friedmud/libmesh,giorgiobornia/libmesh,pbauman/libmesh,benkirk/libmesh,pbauman/libmesh,balborian/libmesh,giorgiobornia/libmesh,jwpeterson/libmesh,svallaghe/libmesh,vikramvgarg/libmesh,hrittich/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,libMesh/libmesh,svallaghe/libmesh,jwpeterson/libmesh,90jrong/libmesh,dschwen/libmesh,jwpeterson/libmesh,pbauman/libmesh,benkirk/libmesh,hrittich/libmesh,libMesh/libmesh,90jrong/libmesh,pbauman/libmesh,dschwen/libmesh,90jrong/libmesh,benkirk/libmesh,balborian/libmesh,libMesh/libmesh,pbauman/libmesh,dschwen/libmesh,balborian/libmesh