Remove swank-clojure from dependencies.

[r0man]

Hi Jim,

since Emacs/swank-clojure are not playing well together when
there are multiple versions of swank-clojure around, I would
suggest removing it from project.clj and using it via
~/lein/plugins.

Right now I have to delete the swank-clojure jar manually after
each "lein deps" ...

Roman

[jduey]

Will do. Might only do it in the upcoming 0.9.0 release, though.