Fix ignore of modules, simplify exclude

Previously, passing e.g. `ignore: ['buffer']` to a browserify job would not work; it would instead resolve the filepath to the local project directory.

Added a test to confirm the fix.

Glob handling is all we need here: see https://github.com/substack/node-browserify/blob/master/bin/args.js#L93 for where the globs are handled from the command line. See also https://github.com/substack/node-browserify/blob/master/index.js#L255 where both the raw name (e.g. `./package.json`) and `path.resolve('./package.json')` are added to the ignore list.