Automatic Python interface generation working with mockderivedtype example

* Provides access to derived-type and module elements
* Derived types map to standard classes, and Fortran modules to Python modules
* Fortran modules with associated state (module-level variables) also get an
  auxiliary Singleton class with one instance named 'fmod' to hold this
* Derived type instances within modules must have 'target' attribute to be wrappable
* Example test.py updated to demonstrate new functionality
Removed manual wrapper as automatic wrapping now working