qibuild: do not use the cmake API from the worktree

this was a bad idea after all

Change-Id: I7995eebe13f24924b5d872ecb2e22c0b87ea532f
Reviewed-on: http://gerrit.aldebaran.lan/27343
Tested-by: gerrit
Reviewed-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
Tested-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
first draft of the ROS contribution
include Dirk's comments
remove code generation, this is package specific, + cleanups
doc/ros: some udpdates

Change-Id: I9c5cbaeeef46ea1a8530dbee7485a1289c7916bc