Capitalize non-function content words in menu item strings.

Capitalize non-function content words in menu item strings.

* lisp/buff-menu.el (Buffer-menu-mode-map):
* lisp/dired.el (dired-mode-map):
* lisp/emacs-lisp/lisp-mode.el (emacs-lisp-mode-map)
(lisp-interaction-mode-map):
* lisp/emacs-lisp/package.el (package-menu-mode-map):
* lisp/epa.el (epa-key-list-mode-map):
* lisp/menu-bar.el (menu-bar-showhide-tool-bar-menu)
(menu-bar-options-menu):
* lisp/outline.el (outline-mode-menu-bar-map):
* lisp/vc/vc-bzr.el (vc-bzr-shelve-menu-map, vc-bzr-extra-menu-map):
* lisp/vc/vc-dir.el (vc-dir-menu-map):
* lisp/vc/vc-git.el (vc-git-stash-menu-map, vc-git-extra-menu-map):
Capitalize non-function content words in menu item strings.

* lisp/dired.el (dired-mode-map): Add menu item for
`image-dired-dired-toggle-marked-thumbs'.