Prevent starting of redundant servers

Use "--startas" rather than "--exec" in the start-stop-daemon args for
starting a server.

"--exec" checks for an existing process that matches the executable, but
in our case the executable is going to be shown as bash (rather than the
bash script we ran).  So the match would never actually match.  I
suppose I could check for "bash" instead but that seems generic enough
to not be much of a check.

"--startas" does what we want without looking for an executable match.

We're still checking the PID file of course.
Don't make server_loop find the launch script

Remove the need for server_loop to find a server launch script.  Instead, have the command script tell it everything.

This is not an earthshaking change but I prefer this arrangement for a few reasons.  It's nicer just to have two levels of scripts, with the command script as "master", rather than three levels.  In the three-level setup it wasn't explicit (from looking at the command script) what server launch script would be used, or what variables were for server_loop vs. for the launch script... it just seemed inelegant.

In general this form of the code has less "magic" going on.

I also moved myip into scriptlib in the process of this change.

There's still quite a bit of common code between various command scripts.  Might be good to factor that out and dump it into scriptlib.  On the other hand, having every relevant configuration in the command script makes things simpler to understand.