Try adding a signal handler outside of twisted to catch HUP.

This ignores HUP.  We can see about re-reading the config at a later
date.
Revert "Try adding a signal handler outside of twisted to catch HUP."

This reverts commit b98ee530f06f969e1a37eb30bab18ba7005fe167.
Relocate @pcn's fix
Merge pull request #309 from jssjr/add-hup-signal-handler

Add hup signal handler (refactors #198)