Added news about new operator overloading and __getattr__ etc.

Added copyright.tex to all files.
Added descr of check_interval to libsys.tex.
Corrected lotsa typos in tut.tex (thanks to George M. Sipe).
Corrected mktuple (should be newtupleobject) example in ext.tex.

Added some new demos.  Fixed a few others.

Removed a few diagram breaks since Kees' program is now cleverer

macosmodule.c: lots of updates (though playing sound can still hang :-( )

	* Modules/(posix,socket}module.c: more NT changes

	global: Py_MakePendingCalls.  Also guard against recursive calls

	* Include/classobject.h, Objects/classobject.c,
	Python/{ceval.c,bltinmodule.c}: entirely redone operator
	overloading.  The rules for class instances are now much more
	relaxed than for other built-in types
	(whose coerce must still return two objects of the same type)

	Include/modsupport.h: moved getargs() to its own file and
	re-implemented it entirely to support optional arguments, multiple
	arguments without surrounding parentheses
	(when called as newgetargs()), and better error messages

	string

	before concatenating sys.path item and module name

	entirely redone operator overloading.  The rules for class
	instances are now much more relaxed than for other built-in types
	(whose coerce must still return two objects of the same type)

	* Objects/floatobject.c: add overflow check when converting float
	to int and implement truncation towards zero using ceil/float

	* Objects/longobject.c: change ValueError to OverflowError when
	converting to int

	* Objects/rangeobject.c: modernized

	* Objects/stringobject.c: use HAVE_LIMITS instead of __STDC__

	* Objects/xxobject.c: changed to use new style (not finished?)

	whom...)