Remove all white spaces
.htaccess: Update the `Custom 404 page` section

- Provide a more meaningful description.
- Comment out the `ErrorDocument` directive as this project doesn't
  offer the custom 404 page like other projects do.
.htaccess: Remove `php_flag register_globals Off`

The `register_globals` directive is not required anymore as it
defaults to `off` starting with PHP 4.2.0, is deprecated as of
PHP 5.3.0 and removed as of PHP 5.4.0:
http://www.php.net/manual/en/ini.core.php#ini.register-globals

Also, support for PHP 4 has been discontinued since 2007-12-31:
http://php.net/releases/index.php
.htaccess: Add comment about font MIME types

Browsers usually ignore the font MIME types and sniff the content but,
Chrome, shows a warning if TrueType / Opentype fonts aren't served with
the `application/x-font-ttf` / `font/opentype` MIME type.

References:
* h5bp/html5-boilerplate#1317
* http://mimesniff.spec.whatwg.org/#matching-a-font-type-pattern
.htaccess: Remove all `php` configurations

The php directives have been included in the Apache hypertext access
file more as helpful information then to be used out of the box.

Nowadays, the use of the directives is highly dependent on the php
version and the way in witch php is integrated with Apache. This makes
them less usefull by default and just extra code to remove for both
the people that don't use php and the ones that do (especially a newer
version).

Reference: h5bp/server-configs/140