Automatic test scenes job improvements

[oktomus]

• Add a lock system to ensure a job can start if another job is running
• Place the build report in the web server
• Add the commit link in the build report in the travis deploy script
• Don't run tests if no build was deployed since last test
• Use a domain name
• Fix test scenes execution order (should be alphabetically, seems random at the moment)
• Make execution log files of already rendered scenes accessible during execution
• Investigate test scenes that seem to render fine but are marked as failed
• Don't run tests in the build directory

[oktomus]

http://testsuite.appleseedhq.net:8080/