(vc-fetch-master-properties): RCS case: get locking mode.

(vc-fetch-master-properties): RCS case: get locking mode.
CVS case: new state `locally-added'.
(vc-locking-user): Under RCS with non-strict locking, don't trust
the file permissions.  CVS case: change which states count as
"locked".
(vc-consult-rcs-headers): Streamlined. Don't set vc-locking-user if
this is called under CVS.  Under RCS, use a heuristic to find the
value of vc-checkout-model without examining the master file.
(vc-parse-locks): Set vc-checkout-model.
(vc-status): Comment change.
(vc-after-save-hook, vc-after-save): The former renamed to the
latter. Now unconditionally called by `basic-save-buffer', determines
whether the buffer should be "locked" or not.
(vc-mode-line): No longer use dynamic after-save-hook. Changed
references to `automatic' into `implicit'.
(vc-checkout-model): Values are now `manual' and `implicit'.  Derive
the property on a per-file basis, supporting all possible modes.