(speedbar-easymenu-definition-base): Image toggle fix.

(speedbar-easymenu-definition-base): Image toggle fix.
(speedbar-insert-button): Invisible text property fix.
(speedbar-directory-plus): Renamed from speedbar-directory-+
(speedbar-directory-minus): Renamed from speedbar-directory--
(speedbar-page-plus): Renamed from speedbar-file-+
(speedbar-page-minus): Renamed from speedbar-file--
(speedbar-page): Renamed from speedbar-file-
(speedbar-tag): Renamed from speedbar-tag-
(speedbar-tag-plus): Renamed from speedbar-tag-+
(speedbar-tag-minus): Renamed from speedbar-tag--
(speedbar-expand-image-button-alist): Use above renames.