Update to Normalize.css 3.0.1
Use `<!doctype html>` instead of `<!DOCTYPE html>`

Return back to the lowercase doctype in order to be more consistent
with the lowercase of the html tags.

References:

  * h5bp/html5-boilerplate#1522
  * http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#the-doctype

Close h5bp/html5-boilerplate#1522.
Update to Apache Server Configs v2.3.0
Make inline comments from main.css more consistent
Further optimize `tile` images

 * tile.png

     before:        13767 B
     after:         13743 B
     ──────────────────────
     reduction:        24 B [0.17%]

 * tile-wide.png

     before:         6781 B
     after:          6774 B
     ──────────────────────
     reduction:         7 B [0.10%]
Merge branch 'master' of https://github.com/h5bp/html5-boilerplate