Migration of all rock packages to github

Since today, all Rock packages have been migrated to github. This
means that, for packaqes you develop yourselves, you will now have to
have a github account as well as the relevant SSH keys installed.

We are sorry for the hurry. This has been done because gitorious.org
is shutting down permanently.

If you are using Rock's 'stable' flavor to access Rock 14.08, your
installation will update all the URLs automatically. However, if you
use the package set's rock1408 branch, you will still be able to pull
for a month or two and then your installation will fail. The github
migration retained all commits and branches, so you can forward-update
your install by updating the source.yml file to point to the github
repositories. The repository naming scheme has changed so that the
repository names reflect the complete package name
(drivers/orogen/sonar_tritech -> drivers-orogen-sonar_tritech).

gitorious: rock-drivers/sonar_tritech.git
github: rock-drivers/drivers-sonar_tritech.git

For the Rock core team,