[Bro] .bro VIM syntax file

[Martin Casado]

 Not to be outdone .. I'll match Christian's Emacs Mode with a bro-script
 VIM syntax file.
 
And, similar Christian .. no hablo 'Vim Script'  so expect idiosyncrasies.

 http://www.icir.org/twiki/bin/view/Bro/BroVimSyntaxFile

 Cheers,
Martin