Update Modernizr to v2.7.1
Update `.htaccess` file
README.md: Add link to the list of releases

Close #1480.
Docs: Update MDN link paths
Docs: Add anchor for MDN link to meta charset
Clarify the default of only 2 icons

In extend.md, which is linked as source for 'more details' on the
touch-icons and favicon, this commit clarifies that by default two
icons are enough if one doesn't want to use art-direction.
Docs: Add comment about `lang` attribute on <html>

We don't set a default `lang` attribute on `<html>` due to the
discussion in #1110. This commit adds a note about how to set it.

Close #1483.
Docs: Make minor improvements in `extend.md`

* Wrap text at 80 characters.
* Rephrase content from the `Apple Touch Icons` section to limit subject
  to only `apple-touch-icon`s (ref: #1486).
* Other improvements.
Docs: Add note about iOS 7.1 `minimal-ui` property

Ref: #1485.
Close: #1485.
Update `CHANGELOG.md`

* Include missing references.
* Improve consistency.
* Wrap text at 80 characters.
Remove default margin from print styles

Providing a default value (such as `5cm`) for the print margins is
problematic because:

 1) in some browsers, it prevents users from customizing the browser
    print settings
 2) in some contexts (browser/os/printer), the value may be too:
    * small, and the margins may collide with all the different
      headers/footers (URL, date, etc) that are usually printed
      by default
    * big, and the margins will just waste the space

Most browsers provide a default non-zero value for the print margins,
so it's better to not specify a value at all, and just let them handle
this themselves.

See also:

 * http://www.w3.org/TR/css3-page/#at-page-rule
 * https://developer.mozilla.org/en-US/docs/Web/CSS/@page

Close #1477.
Docs: Add note about Chrome Mobile web apps

"Add to Homescreen" feature in Chrome Mobile

Closes #1441.
Remove default foreground color from form elements

Specifying a default foreground color for the form elements can be
problematic when users (often with visual impairments) use a darker
OS/browser theme. Also, the color set on the form elements is quite
opinionated, so developers tend to change it anyway.

Ref: #1390.
Close: #1390.
Update `404.html`

* Link to a more official page for the information regarding Internet
  Explorer's "friendly HTTP error pages", namely:
  http://blogs.msdn.com/b/ieinternals/archive/2010/08/19/http-error-pages-in-internet-explorer.aspx.

* Remove the indentation for the `<head>` and `<body>` tags in order
  to reduce the file size even closer to the 512 bytes limit. This is
  particularly helpful when compression is not enabled.

* Stats:

  - before:

     original size:         1409 B
     gzipped size:           580 B
     ─────────────────────────────
     reduction:              829 B [58.8%]

  - after:

     original size:         1242 B
     gzipped size:           580 B
     ─────────────────────────────
     reduction:              662 B [53.3%]

Ref: #1443.
Update to Apache Server Configs v2.1.0
Docs: Update the `Apple Touch Icons` section

* Add note about `precomposed` not being required anymore, as starting
  with iOS 7, no special effects are applied to the touch icons.

* Add missing touch icon sizes.

Close #1488
Combine the `html` selectors into one rule

Close #1492.
Add `Disallow:` to `robots.txt`

The addition of `Disallow:` is made in order to be compliant with:

  * the `robots.txt` specification (http://www.robotstxt.org/), which
    specifies that: "At least one Disallow field needs to be present
    in a record"
  * what is suggested in the documentation of most of the major search
    engines, e.g.:

      - Baidu:  http://www.baidu.com/search/robots_english.html
      - Google: https://developers.google.com/webmasters/control-crawl-index/docs/getting_started
                http://www.youtube.com/watch?v=P7GY1fE5JQQ
      - Yandex: help.yandex.com/webmaster/controlling-robot/robots-txt.xml

Besides the addition specified above, this commit also:

  * adds a comment making it clear to everyone that the directives from
    the `robots.txt` file allow all content on the site to be crawled
  * updates the URL to `www.robotstxt.org`, as `robotstxt.org` doesn't
    quite work:

      curl -LsS robotstxt.org
      curl: (7) Failed connect to robotstxt.org:80; Operation timed out

Close #1487.