The RCS status is now found by reading the

The RCS status is now found by reading the
master file directly, instead of using rlog.  The properties
retrieved from the master file are kept separately.  The two
main properties, `vc-workfile-version' and `vc-locking-user',
are inferred from those master file properties if the
information cannot be found elsehow.  All properties are
consistently cached now.

(vc-master-info, vc-log-info, vc-fetch-properties): functions
removed.  Their job is now done by `vc-fetch-master-properties'
and `vc-insert-file'.

(vc-fetch-master-properties):  new function, replaces
vc-fetch-properties.  Retrieves all the properties that can be
found in the master file, for all three backends (calls
`cvs status' in the CVS case).

(vc-insert-file):  new function.  Inserts an arbitrary file
into the current buffer, optionally chunkwise, until a certain
regexp shows up.

(vc-parse-locks):  new function.  Translates SCCS or RCS lock
lists, as found in the master files, into lisp lists.  Sets
the new property `vc-master-locks'.

(vc-locked-version):  property removed.  Was unnecessary, and
only referenced in vc-hooks.el.
(vc-head-version, vc-default-branch, vc-master-locks):
new properties.

(vc-top-version):  new name for the old property
`vc-branch-version'.  ("top-version" is better because it
might also be the RCS "head" if there is no default branch.)

(vc-master-locking-user):  replaces `vc-true-locking-user'.
Scans the new `vc-master-locks' property, yielding the master
file's idea of who is locking the current workfile version.

(vc-locking-user):  slightly changed to use the new properties.
Changed the actual property value for an unlocked file to
'none.  This is to distinguish it from an unknown locking
state, which is represented by nil.  The function vc-locking-user
returns nil if the property is 'none, to make it compatible with
the rest of VC.

(vc-consult-rcs-headers, vc-master-locking-user):  adpated to
the new 'none-value of vc-locking-user.

(vc-consult-rcs-headers): fixed bug that prevented
(not vc-consult-headers) from working

(vc-file-not-found-hook): set the default-directory of the new
buffer before check-out. (Otherwise, setting vc-keep-workfiles
to nil doesn't work.)

(vc-occurences, vc-branch-p): functions removed (no longer needed)

Reordered some defuns so they are grouped in a logical way.