Add grunt build, fix lint errors, bump dependencies

* Add grunt build which runs the test specs, and lints the project
* Fixed several lint errors
* Bump backbone to 1.0.
* Moved marionette and associated libs from "dependencies" to
"example-dependencies" since Geppetto itself does not depend on them.
* Bump Marionette versions to latest (used only by example app, not by
Geppetto itself)
* Refactored test specs to use plain Backbone views instead of
Marionette views
* Add bower config for integration with bower.io