Rename apps to components.

Drop `app-` prefix from component main files.

Rename `app.json` to `config.json`.
package: upgrade juggler to 2.0.0-beta2
package: remove gulp
package: add missing dependency: `errorhandler`
Merge pull request #35 from strongloop/feature/rename-app-to-component

Rename apps to components; remove gulp from package.json