dm-elisp: difference-based modules for emacs-lisp

dm-elisp is an emacs-lisp with a very simple module mechanism, that provides the following features:

No import/export declarations.
No name-collision due to the idea of fully-qualified-names.
Almost backward compatible with the traditional emacs-lisp.
Supports information hiding.
Supports nested and/or overlapping name spaces by means of multiple-inheritance of name spaces.