Add to contrib dir a shellscript for automating version updates

This is a *prototype* of an automated-update shell script, and even when tested I think it is probably only appropriate for the contrib directory (perhaps with a pointer to it somewhere in the docs, along with the appropriate warnings about the risks of automating things). Take it or leave it (I won't be offended...). I haven't yet battle-tested this, and would personally appreciate any bug-flushing, regardless whether it gets pulled to the servermon repo or not. Of course if you do pull this then *please* include an extra commit to replace all the license comment-noise at the beginning with whatever is appropriate. That filler was just the sleep-deprivation and tea-overload talking...