function inherit(child, base, properties) {
	    var baseP = base.prototype,
	        childP;
	
	    childP = child.prototype = Object.create(baseP);
	    childP.constructor = child;
	    childP._super = baseP;
	
	    if (properties) {
	        assign(childP, properties);
	    }
	}
simple class inheritance
@param {Function} child
@param {Function} base
@param {Object} [properties]