Use a runtime shim to isolate clojure runtimes for each module.
Build with vertx-2.0.0.final.

This required:

* wrapping the new .expectMultiPart method with http/expect-multi-part
* using/shipping a fork of clojure that doesn't leak memory (we'll
  switch back when CLJ-1125 is merged and a version of 1.6.0 is
  released)

This commit also includes tests to confirm isolation works. With
isolated runtimes, moving to 2.0.0-final has the side effect of making
the integration tests much, much slower, since each one has to load
all of the clojure classes each time. C'est la vie.