ENH: adjust infoSwitch to report host subscription (related to #531)
this compact form shows the subscription per host in the unsorted mpi order
nProcs : 18 Hosts : ( (node1 6) (node2 8) (node3 4) )
This provides a succinct overview of which hosts have been subscribed or oversubscribed.
The longer list of "slave.pid" ... remains available on the InfoSwitch 'writeHosts'