Rename on-connection-* into tunnel-*

   .. and simplify related code.
Increase accept-process-output timeout to 0.05 on ssh connection

 Keeping it very low makes Emacs pinging continuously up to the point that C-g
 doesn't work anymore. This happens mostly on windows but people reported this
 on linux as well. It doesn't harm to have it higher in this particular
 place. It's not noticeable and the process returns faster on any input
 anyways. Better safe than sorry.