run_serial and run_parallel return single result for same hostname

[loadtheaccumulator]

While not typical to run the same command against the same hostname as the same user, would be nice to go ahead and handle the results when the same hostname is listed more than once. Currently, the last run into the dictionary[hostname] wins.

Multiple serial and async to the same host for the same command under the same user can currently be handled by calling g.run and g.run_async directly and managing results accordingly.

A possibility is to use our rpyc connection naming scheme and track with user@hostname:# in the hash for 2<n as opposed to dict[hostname][n]. The multi-array will definitely break existing code.