• Changed default behavior of 'use XML::Generator' to not attempt to export
  AUTOLOAD. Removed ':noimport' option.
  
• Allowed more than two components in a namespace, to allow explicit xmlns:
  attributes to be output on demand. Introduced '#default' token.
  
• Improved output aesthetics when there are lot of attributes and the generator
  was configured with the 'pretty' option.
  
• Added allowedXMLTags (alias to allowed_xml_tags) and qualified_attributes
  (alias to qualifiedAttributes) to rationalize interface.