Update Elisp snippets.
Update Elisp snippets.

 - Add section IELM
 - Add new dired-mode snippets
 - Refactored headlines

caiorss/Emacs-Elisp-Hacking,caiorss/Emacs-Elisp-Programming,caiorss/Emacs-Elisp-Programming,caiorss/Emacs-Elisp-Hacking,caiorss/Emacs-Elisp-Hacking