Add task to remove console.log (see #1147 & #1243)

Added a new Grunt task to the build process to remove `console.log` statements. This is important for production since, in some versions of IE, the `console` object is only created after opening the Developer Tools.

Other calls like `console.warn` are kept since they maybe useful in production. An example from the source:

```javascript
console.warn("You need to include froogaloop for vimeo to work");
```

This does not update the `build` dir because files were already slightly different when I ran `grunt` on the master.