Updates the Parser so that it now supports the XML namespaces

Also ensures that the encoding of attributes is XML, rather than HTML
Updates the parser to be PHP 5.3 compatible
More PHP 5.3 fixes
Ensures that the XML encoding only happens if ENT_XML1 is defined
Ensures that the argument to 'defined' is a string
Merge pull request #4 from hobnob/features/namespaces

Updates the Parser so that it now supports the XML namespaces