Move to Git as SCM system

AS part of the efforts to improve refactoring, branching and merging, we should move to GIT as our SCM system.

GIT is available through SBForge.org as part of FIsheye.

We are already using GIT for the integration test configurations and the SB-Pillar. Mikis and Michael has also been using git-svn on the rest of the codebase for the past couple of months.