v4.0.1

• Issue #213: Fix signature for -[NSObject forwardInvocation:]

  Reported by user "pyrocat"

• Updated metadata for Xcode 9.1

• Changes to PyObjCTools.TestSupport to be able to include/exclude tests
  based on the minor release of macOS.

• Some tweaks to fix test failures when running on OSX 10.5, 10.6, 10.9.

NOTE:

The stacktrace formatting of in PyObjCTools.Debugging (from the
ExceptionHandling bindings) don't work for PPC binaries because symbol
resolution doesn't work.

This is a known issue that won't be fixed.