Fixes for the family of %interface macros for overloaded methods

When C++ methods are not able to be overloaded in a derived class,
such as when they differ by just const, or the target language
parameters types are identical even when the C++ parameter types
are different, SWIG will ignore one of the overloaded methods with
a warning. A %ignore is required to explicitly ignore one of the
overloaded methods to avoid the warning message. Methods added
in the derived classes due to one of the %interface macros are now
similarly ignored/not added to the derived class.

The adding of additional methods into the parse tree is now more
robust and complete resulting in support for %feature and %rename
for the added methods.

Closes #1277

Examples/test-suite/common.mk

@@ -308,6 +308,7 @@ CPP_TEST_CASES += \
 	multiple_inheritance_abstract \
 	multiple_inheritance_interfaces \
 	multiple_inheritance_nspace \
+	multiple_inheritance_overload \
 	multiple_inheritance_shared_ptr \
 	name_cxx \
 	name_warnings \