Eliminate some warnings founded by flycheck
Diminish yas-minor-mode
Update README

* Add link to "Unofficial Windows Snapshot"
* Rewrite information about MELPA
* Add links to EmacsWiki and WikEmacs
Enable smartparens-mode only on some modes

* If both paredit and smartparens are turn on, `(' becomes the one
  defined in smartparens. I prefer Paredit over smartparens in lisp
  modes.
* Turn on smartparens-mode in markdown-mode.
Tweak paredit indicator on mode Line

Do not remove paredit indicator on mode line. Keep it so that we can
distinguish it from smartparens.