Python function annotations removed from -py3 option.

Python function annotations containing C/C++ types are no longer
generated when using the -py3 option. Function annotations support
has been moved to a feature to provide finer grained control.
It can be turned on globally by adding:

  %feature("python:annotations", "c");

or by using the command line argument:

  -features python:annotations=c

The implementation is designed to be expandable to support different
annotations implementations. Future implementations could implement
something like the following for generating pure Python types:

  %feature("python:annotations", "python");

or typing module types to conform to PEP-484:

  %feature("python:annotations", "typing");

Closes #1561
Issue #735

Examples/test-suite/python/Makefile.in

@@ -48,6 +48,7 @@ CPP_TEST_CASES += \
 	li_std_wstring_inherit \
 	primitive_types \
 	python_abstractbase \
+	python_annotations_c \
 	python_append \
 	python_builtin \
 	python_destructor_exception \