Whitespace.
Tracking whether an attribute is a non-optional ID field.
Added the map type.

All unit tests pass.  Now for the real test.
Adding event to notify when all of the attributes have been processed.

This will simplify code in both AvroSchemaGenerator and
XmlSchemaStateMachineGenerator.
Cleaning up the XmlSchemaStateMachineGenerator to generate the element
state information once all attributes have been reached.
Generating maps.  All unit tests pass.
Need to rethink how to store MAP information.  Saving here.
This time, track the path indices involved in co-located maps, not just
occurrence information.
Preparing to attach the map information to the path node itself.