Updated hector_quadrotor.rosinstall

Package message_to_tf has been moved from hector_common to hector_localization.
hector_quadrotor_gazebo: added launch file for two quadrotors

Conflicts:

	hector_quadrotor_gazebo/launch/spawn_quadrotor.launch
hector_quadrotor: created new package hector_quadrotor_model and moved
all gazebo plugins to hector_quadrotor_gazebo_plugins
hector_quadrotor: created new package hector_quadrotor_model and moved all gazebo plugins to hector_quadrotor_gazebo_plugins
Merge branch 'groovy-devel' into hydro-devel

Conflicts:
	hector_quadrotor.rosinstall
	hector_quadrotor_gazebo/launch/spawn_quadrotor.launch
	hector_quadrotor_gazebo_plugins/CMakeLists.txt
	hector_quadrotor_gazebo_plugins/src/gazebo_quadrotor_aerodynamics.cpp
	hector_quadrotor_gazebo_plugins/src/gazebo_quadrotor_propulsion.cpp
	hector_quadrotor_gazebo_plugins/src/gazebo_quadrotor_simple_controller.cpp
	hector_quadrotor_gazebo_plugins/src/gazebo_ros_baro.cpp