Web plugin example for backbone

This one shows quite a bit of things we can do to improve the integration into a backbone app.

This uses the TodoMVC to show how the clouds could be saved in local storage for later, and lays the ground work to  how the extra functionality (save as svg and png) could be exposed so they can be integrated into an existing backbone app...

TODOs which this sample shows:
* make the model able to move between the d3 and backbone without data loss... right now its converting the backbone model into an object and sending that to the d3, how could we make it possible to send the actual bacbone model...
* bad practices of loadCloud being global
* something is wrong with the width detection
* the word clouds functions like svg and png export should be exposable
* etc

The next steps on this sample would be to turn this into a backbone MVC component after we have refactored the core eg https://github.com/backbone-paginator/backbone.paginator