There's a built-in "watch" task, along with an open issue to further refine and document it. It's works very well so far, in that a developer can edit arbitrary files and have them all re-linted, unit tested, concatenated, etc as soon as they are saved.

And you could easily have a set of "dev" watch tasks configured, along with "deploy" tasks for minification, etc. There's a lot there, and if you want more just file an issue and we can see what makes sense to implement.