* updating all variables/methods containing Referers
* RENAMING custom segments definition, and custom scheduled reports definition, so that when they load "Referers" segment/report it still works as expected
* RENAMING old archived data so that archived blobs are called Referrers
* Reverting part of 0deb2bbb8d5598200f7adfbc77b190516f919e48
* Update integration tests generating PDF+HTML with images on my dev box (GD 2.1 and PHP 5.5)