* lib/commonio.c, lib/commonio.h, lib/groupio.c, lib/groupio.h,

	* lib/commonio.c, lib/commonio.h, lib/groupio.c, lib/groupio.h,
	lib/pwio.c, lib/pwio.h, lib/shadowio.c, lib/shadowio.h: Added
	splint annotations. The *_locate() and *_next() functions
	currently return an observer. As the structure are often modified
	by the caller, it could maybe be changed to exposed later. (and
	non-const).