Merge pull request #44 from abubeck/hydro_dev

changes for simulation
Merge pull request #46 from ipa-fxm/hydro_dev

bring groovy updates to hydro + make it work
change dependency from gazebo to gazebo_ros
Merge pull request #48 from ipa-nhg/hydro_dev

Hydro update
Merge pull request #47 from mas-group/hydro_dev

change dependency from gazebo to gazebo_ros