add changelogs
0.5.3
New head_center_link
Merge pull request #94 from ipa-nhg/hydro_dev

New head_center_link
Merge pull request #95 from ipa320/hydro_release_candidate

bring back changes from Hydro release candidate
beautify mesh files
Merge pull request #98 from ipa-nhg/collada_mesh

beautify mesh files
Merge branch 'hydro_dev' of github.com:ipa320/cob_common into hydro_dev