Merge pull request #54 from SimonEbner/master-new

Add nvidia-304-driver, check if VNC Display is locked
Update README.md
Update README.md
merging with graphics test
Merge branch 'master' of github.com:ipa-fmw/jenkins_setup
merge
Update README.md
fix install
Merge branch 'master' of github.com:ipa-fmw/jenkins_setup
Merge branch 'master' of github.com:SimonEbner/jenkins_setup
Merge branch 'master' of github.com:ipa-fmw/jenkins_setup
Move setup Vgl into prepare node script
Update readme detailed