update cob4_base stl file
Merge pull request #92 from ipa-nhg/hydro_dev

update cob4_base stl file
New maintainer
Merge pull request #93 from ipa-nhg/hydro_dev

New maintainer
Merge pull request #91 from abubeck/hydro_dev

remove material physic properties of wheels to use default, fixes #90
Merge branch 'hydro_dev' of github.com:ipa320/cob_common into hydro_dev