Move version control related files to the "vc" subdirectory.

Move version control related files to the "vc" subdirectory.
* add-log.el, cvs-status.el, diff.el, diff-mode.el, ediff-diff.el,
* ediff.el, ediff-help.el, ediff-hook.el, ediff-init.el,
* ediff-merg.el, ediff-mult.el, ediff-ptch.el, ediff-util.el,
* ediff-vers.el, ediff-wind.el, emerge.el, log-edit.el, log-view.el,
* pcvs-defs.el, pcvs.el, pcvs-info.el, pcvs-parse.el, pcvs-util.el,
* smerge-mode.el, vc-annotate.el, vc-arch.el, vc-bzr.el, vc-cvs.el,
* vc-dav.el, vc-dir.el, vc-dispatcher.el, vc.el, vc-git.el,
* vc-hg.el, vc-hooks.el, vc-mtn.el, vc-rcs.el, vc-sccs.el, vc-svn.el:
Move files to the "vc" subdirectory.