use r.js proper rather than amd-optimize (bug 1092718, 1078093)

using rjs is so much easier and powerful. It's Gulp's recommended way to build require projects. At first I went with gulp-requirejs which was a bad idea since it was blacklisted and didn't mesh gulp+rjs well. Then I went with amd-optimize which doesn't have enough features. So rjs does everything for us.

- Handles including modules like almond without concatting
- Allows an insertRequire so we don't need init.js
- Handles source maps easily
- Removes views/tests easily while stubbing, reducing our include.js size by a tiny bit
Yeah...it's weird since we're distributing a common gulpfile across multiple projects. Few people have needed to do that so there's not good facilities to do so. So I don't have a clear solution for managing marketplace-gulp dependencies within projects besides maintain them manually (which after everything settles I hope we don't have to do much).