Keyboard default config object merged into options twice

[cgilboy]

It appears that Keyboard.DEFAULT object is merged twice into the options object that is used to construct the Keyboard module.

This happens once in expandConfig quill.js where they have been plucked off of the Keyboard.DEFAULTS on line 349 viamoduleClass.DEFAULTS, and then again later in the Keyboard constructor.

I'm not sure what the project strategy is for configuring module defaults, but this double-merge seems unintended.