Modified Files:
 	Utility.py -- commited a mistake. fixed.

 ----------------------------------------------------------------------

Modified Files:
 	Utility.py -- Added a parameter to Collection class constructor,
		'name' is the default attribute used for keys but one
                 can specify whatever key they want.

        XMLSchema.py -- Used the above parameter to make Collection
		instances use the appropriate 'attribute' as key.

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I fixed that fact that Notation and Entity were not be found. I changed them
to use the qualified name like the rest of the symbols from xml.dom.minidom.

I also discovered that a RecursionError was being thrown, but RecursionError
didn't exist. I created simple sub-class of Exception to rectify this.