add constructorName

[peterdenev]

If a constructor have a name:

var Person=Class({
 init:function Person(){
 }
})

Class name can be get:

Person.constructorName
//or
var p = new Person();
p.class.constructorName

P.S. not the best way but works.
N.B! It gets the "init", "_init", "$init" methods, but didn't look up for inherit data

[peterdenev]

As the commits say:

• define as UMD module (for ComminJS/RequireJs/normal global)
• when using some sort of module loader (AMD) getting caller gets in infinite loop, so I set the max depth=20 (for now)
• when creating Class property now can be set null or undefined
• each class nas a collection of all interfaces that implements (inherited too)
• instanceOf now check for Interfaces too

(Check out my repo for TypeValidation that can be used with ZNOW too)