manifest.xml hidden in all packages

Having both a ``manifest.xml`` and ``package.xml`` in each package is causing a lot of problems with ``rosdep install`` commands when installing from source. This issue has already been resolved in https://github.com/ros-controls/ros_control/pull/108 and I am just extending it to all packages in ros_controllers in this PR. This is a fix for the Gazebo issue:
http://answers.gazebosim.org/question/4134/installing-gazebo-19-on-ros-groovy/?answer=4138#post-id-4138

To make enabling rosbuild support easier I created and documented a script for allowing manifext.xml to be enabled quickly.

@adolfo-rt you are the main person I know who is affected by this