adding sensors launch files
adding gps plugin and removing redundant launch file
adding basic GPS processing to the simulation
launchfile changes to expose parameter setting
Merge branch 'simulator_cleanup' of https://github.com/husky/husky_simulator into simulator_cleanup

Conflicts:
	husky_gazebo/launch/husky_sensors_empty_world.launch
fixed up robot_pose_ekf topic remaps to make sure GPS is linked up to robot_pose_ekf
merged hydro-devel for a pull request back in
combining launch files and adding sensor enable params
Merge pull request #6 from husky/simulator_cleanup

Simulator cleanup

Added gps plugin and basic robot_pose_ekf launch file + LIDAR output.