Add `auto` to the GA tracker create method

The Google Universal Analytics now supports automatic cookie domain
configuration simply by adding `auto` to the analytics tracker create
method: `ga('create', 'UA-XXXX-Y', 'auto');`.

From https://developers.google.com/analytics/devguides/collection/analyticsjs/domains#auto:

  "Automatic Cookie Domain Configuration simplifies cross domain
   tracking implementations by automatically writing cookies to the
   highest level domain possible when the auto parameter is used.
   When used on the domain www.example.co.uk, it will try to write
   cookies in the following order:

     1. co.uk
     2. example.co.uk
     3. www.example.co.uk

   Analytics.js will fail to write a cookie on co.uk but will succeed
   on example.co.uk. Since a cookie was succesfully written on a higher
   level domain, www.example.co.uk will be skipped"

So, when this parameter is omitted (as it was prior to this commit),
Google Universal Analytics will default to using `location.hostname`,
which will include the subdomain, preventing websites with multiple
subdomains from being able to automatically track unique users across
those subdomains.

Note: The `auto` parameter is now officially part of the recommended
Google Universal Analytics snippet.
https://developers.google.com/analytics/devguides/collection/analyticsjs/

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Ref: https://developers.google.com/analytics/devguides/collection/analyticsjs/domains#auto
Close: h5bp/html5-boilerplate#1562.
Docs: Make minor improvments in `html.md`
Add `/.editorconfig` file

The addition of the `/.editorconfig` file is made in order to
encourage and help developers and their teams define and maintain
consistent coding styles between their different editors and IDEs.

By default, `/.editorconfig` includes some basic properties that
reflect the coding styles from the files provided by default, but
users can easily change them to better suit their needs.

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Since users need to install a editor/IDE plugin in order for the
properties from the `/.editorconfig` to be applied, we were reluctant
to add this file in the past (see: h5bp/html5-boilerplate#1124).
Nowadays however, the EditorConfig project provides plugins for most
of the popular editors/IDEs (see: http://editorconfig.org/#download),
plus, more and more developers are using it.

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Ref: http://editorconfig.org/

Close: h5bp/html5-boilerplate#1561
       h5bp/html5-boilerplate#1564
Docs: Remove `minimal-ui` related information

The `minimal-ui` viewport property was introduced in iOS 7.1,
but it will no longer be supported in iOS 8.

Ref: https://developer.apple.com/library/prerelease/ios/releasenotes/General/RN-iOSSDK-8.0/#//apple_ref/doc/uid/TP40014223-CH1-SW83
Close: h5bp/html5-boilerplate#1565
Docs: Remove gendered pronoun from `faq.md`

Close: h5bp/html5-boilerplate#1566.
Update to Apache Server Configs 2.7.0
Docs: Add information about PHP's built-in server

Ref: http://php.net/manual/en/features.commandline.webserver.php
Close: h5bp/html5-boilerplate#1569.
Remove need to readjust margins in `404.html`

Since some of the users prefer to just modify the placeholder 404
page instead of replacing it with their own, this commit makes it
easier to do that by allowing them to modify the content without
worrying about readjusting the margins.

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Note: The different in size compared to the old 404 is negligible:

 * old 404:

   original size:         1242 B
   gzipped size:           574 B

 * new 404:

   original size:         1274 B
   gzipped size:           570 B

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Ref: h5bp/html5-boilerplate#1567.
Close: h5bp/html5-boilerplate#1567.
Change the architecture of the project