hector_quadrotor_controller: fixed segfault when using nested QuadrotorInterface handles
hector_quadrotor_model: added boolean return value for configure() methods
hector_quadrotor_gazebo_plugins: aerodynamics plugin should apply forces and torques in world frame
Merge branch 'hydro-devel' into ros_control

Conflicts:
	hector_quadrotor_gazebo_plugins/src/gazebo_quadrotor_propulsion.cpp
hector_quadrotor_model/hector_quadrotor_gazebo_plugins: fixed configuration namespace and plugin cleanup
Merge branch 'hydro-devel' into ros_control
hector_quadrotor_model: output drag forces in body coordinate system and added orientation input

This commit partially reverts 9b5e85f2248cf139c3a1c336348ca29ed70fb093.
Merge branch 'hydro-devel' into ros_control
hector_quadrotor_gazebo_plugins: disabled separate queue thread for the aerodynamics plugin
Merge branch 'hydro-devel' into ros_control