The typical method of adding JavaScript and CSS libraries (e.g. jQuery, Bootstrap, and AngularJS) to Salesforce environments is to locate a library's download, download it, then upload it to Salesforce, then figure out the structure of the files so that you can use them from Visualforce. Using [WebJars][1] as a basis, I've created an easy way to add libraries to Salesforce, called [Force WebJars][2].

Here is a quick demo:
<iframe width="640" height="480" src="https://www.youtube.com/embed/CxlP_Q596fg" frameborder="0" allowfullscreen></iframe>  

[Give it a try][2] and let me know how it goes!

BTW: The [source is on GitHub][3].

 [1]: http://www.webjars.org
 [2]: https://forcewebjars.herokuapp.com/
 [3]: https://github.com/jamesward/forcewebjars