Update to latest ember-dev.

`ember-dev` has been updated to only include `bundler/gem_tasks` when actually
releasing a gem.

`ember-dev` now uses the dasherized project name (from `ember-dev.yml`) for
the generated spade file. This allows us to test multiple projects at once
without having a naming collision on `ember-spade.js`.

I also updated `ember-source` to 1.1.1 (latest stable).