Remove remaining __cmp__ in comtypes

[junkmd]

In Python3,

The cmp() function should be treated as gone, and the __cmp__() special method is no longer supported.
https://docs.python.org/3/whatsnew/3.0.html#ordering-comparisons

However, they are still contained in comtypes.

comtypes/comtypes/client/lazybind.py

Lines 129 to 132 in afc6488

	def __cmp__(self, other):
	if not isinstance(other, Dispatch):
	return 1
	return cmp(self._comobj, other._comobj)

comtypes/comtypes/GUID.py

Lines 45 to 48 in afc6488

	def __cmp__(self, other):
	if isinstance(other, GUID):
	return cmp(binary(self), binary(other))
	return -1

comtypes/comtypes/__init__.py

Lines 592 to 605 in afc6488

	def __cmp__(self, other):
	"""Compare pointers to COM interfaces."""
	# COM identity rule
	#
	# XXX To compare COM interface pointers, should we
	# automatically QueryInterface for IUnknown on both items, and
	# compare the pointer values?
	if not isinstance(other, _compointer_base):
	return 1
	# get the value property of the c_void_p baseclass, this is the pointer value
	return cmp(
	super(_compointer_base, self).value, super(_compointer_base, other).value
	)

Remove these dead code and modernize the codebase.