Created build system using grunt

As proposed in #11, I've created a grunt based build setup with the following tasks:

* task for jsbeautify & settings (minor formatting changes due to first indentation)
* task for jshint
* task for minification (UglifyJS2)
* task for documentation (yuidoc) (Due to added package.json, some meta info added)

The jsbeautify format is close to what was existing, but one detail has all the lines touched: the indentation within the builder function is at level one already.

Minification produces closely to what was existing; I only added one option to have the statement separator kept the same. I don't know the options that were used so far.

Since there is a task for yuidoc, I also added that one. Because of the added meta-info in package.json, those files were touched as well.