Improve handling of FORTRAN 2003 classes

These changes (summarized below) provide updates that allow FORTRAN 2003 style classes to be represented appropriately in documentation and distinguishes them from FORTRAN modules. There are also additional changes to the generation of highlighted/linked source code for statements related to FORTRAN class definitions.

- Changed FORTRAN modules from CLASS_SEC to NAMESPACE_SEC
- Updated argument linking to search containing namespace for type definitions
- Updated FORTRAN code generation to handle F2003 style classes
- Added other language features to FORTRAN code generation
- Fixed bug with RTF generation and SHOW_NAMESPACES=NO