cm: Replace Grunt/RequireJS with Gulp/Browserify. Yes, I know, this sounds like it's 2014 or something, and cool kids are now actually on webpack or whatever. Anyway, besides the change to a `gulpfile`, it also moves all dependencies over to `npm` (via the `package.json` file), which cleans up the repository nicely, and replaces awkward JS imports with simpler `require` statements.

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