Allow backticks before org-mode emphasis markup.
Enable yasnippet source for auto-complete.
Start using expert UI for org-export-dispatch.

Useful because it keeps export dispatcher from covering existing
windows.
org-mode: Define keyboard macro for wrapping stretches of text with
comment block delimiters.
Improve git-gutter setup:

- Make sure modeline doesn't show lighter.
- Don't add key bindings to global map. Turn them on locally when
  git-gutter-mode is enabled.