Merge pull request #27 from tribal-tec/master

Allow empty sessions to clear all content
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Cleanup
dcStream performance unit test
extend dc stream performance test
Merge branch 'master' of https://github.com/BlueBrain/DisplayCluster
Bugfix in output
CR #47
Fix unit test configuration file
Merge pull request #47 from eile/master

dcStream performance unit test and related cleanups