[ModuleGenerator] Changes in the scaffold of YUI modules

Hi guys,

Here's what I added to the project:

 - removed the (wrong) instanciation of module in the module scaffold (https://github.com/popox/generator-yui3/commit/4e8178605ab420d02d6a550d44cf0eb908b6a14e#diff-6af6cb123377f197d17e29389a1dbd07L13)
 - removed the ```@constructor``` yuidoc in the class doc
 - Added a namespacing possibility for the module generation (new prompt in the module generation)

Let me know if it suits you!