new ssh connections cause bbs to be freeze up for a short period

[Jeff Quast]

as the on-connect negotiation occurs in a thread, esp. paramiko's, whose ssh negotiation consumes so much cpu that the mainthread handling the event loop is blocked (~1-2 seconds) -- so all other user's i/o is also similarly blocked.

The fix would be to delegate this work to a sub-process, though I'm not sure this is very easily done, as we've got to either safely and carefully pass off the socket (file handles) -- or do some additional abstraction. needs careful study.