Detach the 'chown' action from the symlink-action, make sure a failed chown doesn't screw up the release process.

Chown can only be run by root or for groups of which you're a member, which means that in situations where a user is deploying into a folder in which write access is granted but which is actually owned by another user, chown will fail and cause the deployment to report as failed.
Connect to remote server without a username if none has been provided.

This makes it possible to leave the 'user' config parameter out of the environment/hosts config, so every developer in a team can run this from their own machine without having to alter the config files.