Edited Apache setup examples to work with 2.4

## Changes

### Added `.conf` file-extension. Fixes #5.

As seen in issue #5 it seems like the missing file extension causes confusion to the `a2ensite` command in Apache 2.4.

### Added a note about apache 2.4 new access control.

Another issue I ran into. Somehow it wouldn't let me in without this directive. Someone wrote [an article](http://dabase.com/blog/AH01630:_client_denied_by_server_configuration/) describing a similar problem.