Expanded class hierarchy of EasyRdf_Literal

class \EasyRdf_Literal
- class \EasyRdf_Literal_Boolean
- class \EasyRdf_Literal_Date
- class \EasyRdf_Literal_Decimal
- class \EasyRdf_Literal_HexBinary
- class \EasyRdf_Literal_HTML
- class \EasyRdf_Literal_Integer
- class \EasyRdf_Literal_XML