Add checkall/sshto scripts.

sshto: like 'ssh <hostname> <command>' but uses a configname instead of
a DNS hostname, and falls back to a serial port if the host isn't accessible
by network.

checkall: pings all configured hosts in parallel, and prints a one-liner
describing which hosts are up/down.  (Suitable for running in a loop to
monitor the status of your network.)

Change-Id: I40990fbb293e6c57870d7526575832dc93b16818
3 files changed