Various Racket Updates

No, I have not fallen off the face of the earth. Lets just say I've been preoccupied.

There have been several updates on the Racket front. In no particular order:

1. Racket has been yanked from Metasploit and replaced by Todd's Packetfu. As cool as it was to have Racket powering so many interesting bits of metasploit for as long as it did, in the end I don't get paid to maintain Racket and I simply couldn't keep pace with what the Metasploit team needed with my full time job situation the way it is.
2. Hosting of the Racket gem has moved to rubygems.org, so now you can just 'gem install racket'. Source and the SVN repository are still in the original places if you are so inclined.
3. bit-struct was added as a dependency for Racket. At one point in time, bit-struct was not available as a gem so I couldn't require it in the gemspec. Now it is so now I can.
4. pcaprub is not currently a required dependency for Racket, though I'm still at a bit of a loss as to how you'd get any value out of Racket without pcaprub. With that said, I have had a request to make it not required, and my decision, at least for Racket 1.0.11, was made easier by gem breakage in pcaprub 0.11 and 0.11.1 that are still getting resolved.