* lisp/net/eudc-bob.el: Use lexical-binding; Misc simplifications

* lisp/net/eudc-bob.el: Use lexical-binding; Misc simplifications

(eudc-bob-generic-keymap, eudc-bob-image-keymap)
(eudc-bob-sound-keymap, eudc-bob-url-keymap, eudc-bob-mail-keymap):
Move initialization into declaration.  Use RET rather than `return`.
(eudc-jump-to-event): Delete; use `mouse-set-point` instead.
(eudc-bob-save-object): Rewrite using `write-region`.
(eudc-bob-popup-menu): Use `popup-menu`.