Move jQuery dependency to peerDependencies and add David-badges

As a plugin you should depend have your dependency as a peerDependency.
jQuery should also be a devDependency, as it's used when running tests.

Source: http://blog.nodejs.org/2013/02/07/peer-dependencies/

In addition I added the nice dependency-badges from https://david-dm.org

Also, if you'd like med to remove the whitespace-changes before merging I'd be happy to do so