feat(emacs/lean-settings.el): add customization-settings file
feat(emacs/lean-util.el): add lean-util.el
refactor(emacs/lean-mode.el): clean up, add license
feat(emacs/lean-mode.el): add whitespace-mode to lean-mode-hook
fix(bin/lmake): pass lmake option to makefile
feat(emacs/README.md): add README.md