Changes to support the return of samples

After a lot of back and forth, I decided to checking in the dependencies (jquery etc).
Otherwise downstream repos are required to run bower/grunt.
However to update them, all one has to do is change tools/bower.json and run ./tools/update.sh
The update script actually does a npm install to get grunt (that we use for the grunt-bower-install task) and then runs grunt (which internally does a bower install followed by some cleanup).

Also I have added a gen repo that contains a cordova_plugins.js and the plugins in individual files just like they would be in a cordova generated projects.
If cordova.force.js changes, one should run./tools/update.sh to regenerate those files.
Again having them checked in simplifies the life of any consumers of the rep.