gh-134 Scala version of HttpServerFileUpload and fix uploadHandler()

* HttpServerRequest.uploadHandler should take a function with the
scala version of HttpServerFileUpload
* Added tests to verify form and file upload
* MultiMap adapter needs to be shallow copy over the Vert.x MultiMap.
Otherwise, changes to underlying Vert.x MultiMap were not visibible
to Scala consumers.
Update to Vert.x 2.1RC1