ChangeLog: Prepare for 1.2.0-RC1.
Rename prepare_dist_from_bzr.sh to prepare_dist_from_git.sh
scripts/prepare_dist_from_git.sh: Change to use Git.
scripts/prepare_dist_from_git.sh: Check out requested branch and not HEAD.
Merge pull request #16 from wilx/1.2.x

Merge.