lisp/vc/*.el: Use lexical-bindings in all the files

lisp/vc/*.el: Use lexical-bindings in all the files

Also remove some redundant `:group` arguments.

* lisp/vc/vc.el (vc-ignore): Autoload.

* lisp/vc/pcvs-util.el (cvs-every, cvs-union, cvs-map): Delete functions.
* lisp/vc/cvs-status.el: Require `cl-lib` at runtime.
(cvs-tree-tags-insert): Use `cl-mapcar` and `cl-every` instead.
* lisp/vc/pcvs.el: Require `cl-lib` at runtime.
(cvs-do-removal): Use `cl-every` instead.

* lisp/vc/ediff-init.el: Require `ediff-util` (for `ediff-cleanup-mess`
and `ediff-default-suspend-function`).

* lisp/vc/pcvs-info.el (cvs-fileinfo<): Remove unused vars `subtypea`
and `subtypeb`.

* lisp/vc/vc-git.el:
* lisp/vc/vc-bzr.el: Require `vc-dispatcher` at runtime for
`vc-do-async-command`.