=pro enable cross builds

* changed zeromq-scala-binding library
* added dependency helpers from master by Johannes.
* modified build-release task to include distributions from cross builds
* removed tar-zip step from release script, because tgz package is not used from the website
* release script now releases for all crossScalaVersions
* dry run is the default now

I will port to master some of this.
So are you sure that this version is identical to 0.0.7? I mean you are changing the version used in the 2.10.x build of 2.3.x to enable the 2.11.x build.