Updated build process for grunt 0.4.0

PR for review

Changes : 
- Added sourcemaps
- Added code coverage reports (`reports/coverage/`)
- Added complexity/lint reports (`reports/`)
- grunt.js -> Gruntfile.js along with configuration updates

Points of concern :
 - Need input from contributors to see if the workflow stays the same for custom cases
 - Licenses on minified builds are in flux while [grunt-contrib-uglify#22](https://github.com/gruntjs/grunt-contrib-uglify/issues/22) is pending

Main entry points to grunt stay the same, `grunt` builds, `grunt test` tests

Derick, I need to know how you personally run your tests in order to accomodate any different flows.

Grunt 0.4.0 hasn't dropped yet (though hopefully will very shortly) but I didn't want to sit on this branch much longer since the reports and sourcemaps are valuable now.