Update EIEIO documentation because of namespace cleanup.

Update EIEIO documentation because of namespace cleanup.

* eieio.texi (Introduction): `class-of' is obsolete.
(Predicates, Basic Methods): Adapt function names to namespace
cleanup.
* NEWS: Add missing renames to EIEIO section.  Also, no functions
were removed but only made obsolete.  Class field accessors were
always purely internal, so remove that remark.  Add markup.