more alias command.
rebind `M-SPC' and `M-S-SPC'.

use `M-\' to switch input source on OS X.
bind "M-SPC" to `ace-jump-mode'.
bind `M-S-SPC' to `cycle-spacing'.
52evil-mode.el: bind "TAB" to `indent-for-tab-command' in evil-motion-state-map
lowercase all tags and update org-drill config.
enable org-mac-link and bind it to "gl" of evil normal mode and delete evil-little-word.