Live deploy as a nightly version

I've added the live deploy option as a nightly version. This future is enabled by setting the "live-deploy-mode" flag to true.

review @devoncarew @ussuri
Copy-pasting from an offline discussion: change `startLiveDeploy` to `startLiveDeploy(Project currentProject, {void onError(var exception)})`, and pass a lambda invoking showErrorDialog to it.