templatize the envvars file

The envvars file (typically installed into /etc/apache2/envvars) sets some environment variables that are used by the init script.

It sets the user to run as, group, pidfile location, etc.

Previous versions of the cookbook didn't include this file, so the init system would be using the wrong pidfile location, for example, and wouldn't know how to stop/restart apache.

This version uses the same values that are used in the rest of the apache2 configuration.
only turn rewrite on once
Checking if server_aliases is defined in example
Correct mod_basic/digest recipe names in README

* `mod_basic` is `mod_auth_basic`
* `mod_digest` is `mod_auth_digest`
Merge pull request #156 from Odaeus/patch-1

Correct mod_basic/digest recipe names in README
Added notification hook for gitter.im
Added Gitter Chat badge to README
make the minitests pass on centos. removed authnz_ldap, fcgid and xsendfile modules as they do not get installed correctly on centos and therefore fail the tests
working basic serverspec for centos
satisfy rubocop in regards to commented out code
Added notification hook for gitter.im
work in progress for attributes being passed via properties
Update service_name for Ubuntu 12.04
Merge pull request #106 from kriswallsmith/patch-1

only turn rewrite on once
Merge pull request #152 from fejese/master

Checking if server_aliases is defined in example
add conf*, mods-*, and sites-* directories to test
added test for docroot, lib, apache dir existence and permissions
test for cgibin dir existence and permissions
Update debian-7.4 attributes
added more platform definitions