Catkatinized hector_quadrotor_ptam

rosmake hector_quadrotor_ptam works now.

roslaunch hector_quadrotor_ptam launch_simulation.launch still fails, because:

~/catkin_ws/src/hector_quadrotor/hector_quadrotor_gazebo/urdf/quadrotor_plugins.gazebo.xacro is not found

It seems that quadrotor_plugins.gazebo.xacro.in was not populated into quadrotor_plugins.gazebo.xacro by the build system, but I can't figure this part out.