Merge pull request #7 from ipa-rmb/groovy_dev

latest update from rmb
Merge pull request #9 from ipa-rmb/groovy_dev

manual adjustment of stack.xml
Update README
Update and rename README to README.md
Update README.md
Update readme

Corrected openni_launch command.
Merge pull request #12 from Seanny123/patch-1

I will merge your instructions and correct the inaccuracies. Thanks for your valuable contribution!
Update README.md

Removed one unnecessary step from the installation instructions.
Merge branch 'groovy_dev' of github.com:ipa320/cob_people_perception into 320-groovy_dev