message: README update (mission statement)
diff: * Font Ligatures Support (such as in Fira Code).
  * GPU-acelerated rendering.
  +## Mission Statement
  +
  +The following is an incomplete list of features that contour does or will support.
  +
  +* [x] Available on all three major platforms (Linux, OS/X, Windows 10)
  +* [ ] Terminal Multiplexer Mode (like TMUX/screen) with a graphical as well as a text based frontend
  +* [ ] Multiple Sessions, Windows, Tabs, Panes (like TMUX/screen)
  +* [x] Runtime configuration reload
  +* [x] Font Ligatures Support (such as in Fira Code)
  +* [x] GPU-accelerated rendering
  +* [x] 256-color and Truecolor support
  +* [ ] Key binding customization
  +* [ ] History Search
  +* [ ] Activity/Inactivity/Bell System Notification
  +* [ ] Color Schemes
  +* [ ] Profiles (grouped customization of: color scheme, login shell, and related behaviours)
  +* [ ] Shell Integration (inspired by iTerm2)
  +* [ ] Inline Images (inspired by iTerm2, conforming to their custom VT sequences for compatibility)
  +
  ## CLI - Command Line Interface
  ```txt
  