Gruntify boomerang and add package.json

 Replace most of the functionality in the Makefile with Grunt and npm.

 A new workflow to build boomerang would be:
 ```shell
 $> cd boomerang
 $> npm install
 ...
 $> grunt
 ...
 $> ls build/
 boomerang-0.9.0-debug.js
 boomerang-0.9.0-debug.min.js.map
 boomerang-0.9.0.min.js
 boomerang-0.9.0-debug.min.js
 boomerang-0.9.0.js
 boomerang-0.9.0.min.js.map
 $>
 ```
 This /should/ streamline the process of getting an initial build of
 boomerang.js as fast as possible for the user and removes friction
 towards getting up and running.

 As a side effect using the plugin.json file to configure the plugins
 baked into the final boomerang release, you get an easier to reproduce
 build that makes development of plugins easier.
Depending on who started it in the beginning, that Person should go into the "author" part. 

Everyone else can be added to the "contributors" array of people. 

Take the main documentation for package.json as guidance maybe?
https://www.npmjs.org/doc/files/package.json.html#people-fields-author-contributors

    Excuse my blunder of only adding myself to that List. I'll see if 
    I can get a complete list of all contributors from the commit 
    history in master.