Add bower.json

Adding a bower.json so people can install Team Sass components with [Bower](http://bower.io).

I referenced other Team Sass pull requests here so we can use this as a meta issue.

These PRs are a first pass. A couple things need to be decided before we commit and register the projects as Bower packages.

- Breakpoint is in the Bower registry already. Everything else needs to be checked for naming collisions, and we should probably choose a standard naming convention.
- For each project I excluded tests, but kept the examples.
- The packages register their dependencies, but I'm not sure how this is going to work in practice. [This issue](https://github.com/bower/bower/issues/292) leads me to believe that all dependencies will be installed alongside each other like npm peerDependencies, which would be perfect. Haven't tested yet though.
- Any dependencies outside of Team Sass I set with a git endpoint instead of submitting bower.json PRs. Opinions welcome.