SIGKILL cannot be caught

Node 0.10 seems to reflect the fact that `SIGKILL` [cannot be caught](http://pubs.opengroup.org/onlinepubs/009696699/basedefs/signal.h.html) by throwing an exception when trying to listen to that signal.

This patch removes `SIGKILL` from `service.processListeners` which resolves the failing test in issue #1.