Run a deploy to the test server from TravisCI if tests are passing

[dej611]

Based on this blog post: https://oncletom.io/2016/travis-ssh-deploy/

Instead of using rsync as described in the article, in this PR there are:

• a new config/deploy/travisci.rb configuration
• an encrypted key file to deploy to the target server
• some more lines in the .travisci to setup the correct environment to deploy
• use cap deploy travisci to deploy using the config above

[dej611]

Regenerated the deploy_rsa.enc file as requested.