Small viper clean-up

Small viper clean-up

* lisp/emulation/viper-cmd.el (viper-set-searchstyle-toggling-macros)
(viper-set-parsing-style-toggling-macro)
(viper-set-emacs-state-searchstyle-macros):
Use called-interactively-p on Emacs.
(viper-looking-back): Make it an obsolete alias.  Update callers.
* lisp/emulation/viper-ex.el: Load viper-keym, not viper-cmd.
Use looking-back rather than viper-looking-back.
(viper-tmp-insert-at-eob, viper-enlarge-region)
(viper-read-string-with-history, viper-register-to-point)
(viper-append-to-register, viper-change-state-to-vi)
(viper-backward-char-carefully, viper-forward-char-carefully)
(viper-Put-back, viper-put-back, viper-add-newline-at-eob-if-necessary)
(viper-change-state-to-emacs): Declare.
* lisp/emulation/viper-macs.el: Load viper-mous, viper-ex, not viper-cmd.
(viper-change-state-to-insert, viper-change-state-to-vi): Declare.
* lisp/emulation/viper-mous.el: Do not load viper-cmd.
(viper-backward-char-carefully, viper-forward-char-carefully)
(viper-forward-word, viper-adjust-window): Declare.