Whitespace change in qpol.i.
Create a generator function for qpol iterators.

Makes them an Iterable in Python.
Fix TERule __str__ handling for type_change and type_member rules.
PEP8 fix in SELinuxPolicy.
Add rule_type() member function for qpol_filename_trans_t wrapper.

Eliminates special case in TERule ruletype() member function.
Change wrapper to use decorators instead of overriding member functions.

This eliminates the need for referencing the C extension's generated
member function, making maintenance less error prone.