Allow for better $logroot management

This commit now allows you to set the directory permissions on the default
$logroot directory by exposing $logroot_mode in init.pp. It also adds a
$logroot_ensure parameter to apache::vhost that can toggle the creation of a
vhost's logroot resource.
Added missing syntax highlight to 1st apache::mod::php example
Merge pull request #807 from Ginja/expose_logroot_mode

Exposed $logroot_mode in init.pp
Merge pull request #832 from thatgraemeguy/master

Added missing syntax highlight to 1st apache::mod::php example
Allow multiple balancermembers with the same url

Currently you can't set multiple balancermembers with the same url even
if they are bind to different balancers.

This commit fixes that unwanted behaviour.