Removed PhantomJS
Removed upstart scripts
Removed Python install scripts
Combined xvfb and browser playbooks
Changed Jenkins user base to /home/jenkins
Added wheel dir creation
Moved jenkins_env script
Changed data directory to /var
Install newer version of rake in rbenv role
Added edxlocal role
Remove system packages already installed by common and edxlocal
Added list of Python packages to pre-install
Merge pull request #409 from edx/will/jenkins-refactor-2

Jenkins worker refactor