Make Travis CI limit the Git clone depth even more

In order to speed up the tests a little bit more, inform Travis CI
to limit the Git clone depth to 10 commits (default is 50).

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

e.g.:

  $ time g clone --depth 10 git@github.com:h5bp/html5-boilerplate.git
  ...

  real    0m2.636s
  user    0m0.052s
  sys     0m0.040s

  $ time g clone --depth 50 git@github.com:h5bp/html5-boilerplate.git
  ...

  real    0m3.542s
  user    0m0.064s
  sys     0m0.072s

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Ref: http://git-scm.com/docs/git-clone
     https://twitter.com/travisci/status/288390896339267584
Update the content from the `dist` directory
Remove unneeded comma from `gulpfile.js`

Close h5bp/html5-boilerplate#1591
Minor fix: Use short version of shorthand for margin declaration in 404 template
Docs: Add more info regarding servers and stacks

Ref: h5bp/html5-boilerplate#1572
Close: h5bp/html5-boilerplate#1572
Make Travis automatically update `dist` directory

Configure Travis to automatically update the content from the `dist`
directory by executing a script¹ that will regenerate the content from
the `dist` directory and commit any new changes to the `master` branch.

This change will help in the development process by:

  * ensuring that the content from the `dist` directory is always
    in sync with the rest of the content

  * removing the need to execute the build step locally everytime
    a change is made (especially in the case of trivial changes,
    such as, typos)

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¹ The script (`bin/update_dist_directory.sh`) will only be executed
  if the tests pass, and will only run if the changes are made in the
  `master` branch.

See also: http://docs.travis-ci.com/user/encryption-keys/

Close h5bp/html5-boilerplate#1593
Update content from the `dist` directory [skip ci]
Docs: Add info on disabling phone no. formatting

By default Safari on iOS will automatically inject a `<a href="tel:…">`
when it detects any string formatted like a phone number on the web page
(see: https://cloud.githubusercontent.com/assets/1223565/4230929/90243cd8-398a-11e4-9363-67faf5cb355c.png).

This commit improves the documentation by providing information on
how to disable the automatic detection and formatting of possible phone
numbers in Safari on iOS.

Ref: https://twitter.com/marcosc/status/507897299587313665/
     https://developer.apple.com/library/safari/documentation/AppleApplications/Reference/SafariHTMLRef/Articles/MetaTags.html/#//apple_ref/doc/uid/TP40008193-SW5
Docs: Fix broken link in `usage.md`

Close h5bp/html5-boilerplate#1595
Update content from the `dist` directory [skip ci]
Update Apache Server Configs to v2.8.0
Docs: Fix broken link in `misc.md`

Close h5bp/html5-boilerplate#1596
Update content from the `dist` directory [skip ci]
Update update_dist_directory.sh
Docs: Fix typos

Close h5bp/html5-boilerplate#1600
Update content from the `dist` directory [skip ci]
Docs: Add information about the `robots.txt` file

Ref: h5bp/html5-boilerplate#1554
Close: h5bp/html5-boilerplate#1598
Docs: Provide link to Google's docs on robots.txt

Ref: h5bp/html5-boilerplate#1554
Remove the `cross-domain` phrase from `README.md`

The part about `Cross-domain Ajax and Flash` from the `README.md` file
isn't accurate, as by default:

 * the `crossdomain.xml` file doesn't grant a web client — such as Adobe
   Flash Player, Adobe Reader, etc. — permission to handle data across
   multiple domains

 * the Apache server configs, do not allow cross-origin access to all
   resources, unless the user enables that behavior
Futher optimize `tile.png` and `tile-wide.png`

 * `tile.png`:

    before:        13743 B
    after:          3495 B
    ──────────────────────
    reduction:     10248 B [74.56%]

 * `tile-wide.png`

    before:         6774 B
    after:          1864 B
    ──────────────────────
    reduction:      4910 B [72.48%]

Close h5bp/html5-boilerplate#1604.