concat -> concat_sourcemap - one React JS file unhappy, so commenting that out. Set up fake sources because concat_sourcemap will complain otherwise.  Need to add at least one template and coffee file, just so the process has something real to work on
underscore.string
handlebars is a templating engine, the other backbone ones I saw in a course I am taking.  We'll see what use they are when i start on Backbone
placeholder for handlebars
why not - means it forces a match to stuff in, say, Gruntfile.js
coffeeify and grunt-browserify