Tweak bower.json settings

Some refinements based on the [bower.json specification](https://github.com/bower/bower.json-spec) and to make it more aligned with the npm [package.json](https://github.com/thoughtbot/bourbon/pull/483).

- Added `description`
- Added `license`
- Added `keywords`
- Added `authors`
- Added `repository `
Good eye, again! This seems to work fine, but I do think we should point right to the repo with the `git://` protocol. Changed.