Add gitignore, kitchen-ci files
Add some tests and documentation

This is done by split the interface pillar value instead of using a proper
list so it behaves exactly the same as before for simple 1 interface cases
(no need to refactor one's pillar files).

The resulting is something like:

  Listen 1.2.3.4:80
  Listen [2001:abc:def:100::3]:80

  <VirtualHost 1.2.3.4:80 [2001:abc:def:100::3]:80>
  ...

Added example shows 503 code instead of "It works!" page.

- Added more modules and configuration options
 - Renamed sls files to reflect what they do.
 - added mpm options for Debian

apache.vhosts.standard

They no longer are dependencies of this formula.

This reverts commit f7b14ec169.

The link to the installation and usage instructions does not work. This fixes it.

apache.vhost.standard --> apache.vhosts.standard