Compilation fixes for send/receive(set)
Compilation fixes for send/receive(set)

I thought we'd been communicating sets for years, but apparently
set_union and set_intersection are all I ever used...

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