Update to 1.3 and deal with Gentoo bug 383179

I added an ebuild for the 1.3 release. I also had to tackle some issues with zlib as some macros had their names changed by https://bugs.gentoo.org/show_bug.cgi?id=383179. There is probably a better way to deal with it but I just did the same sed command on the relevant files inside the arango tree. This may need to get back ported to your other ebuilds as anyone that has headers from zlib>1.2.5.1 available on their system will probably find that they get used and cause compile issues similar to http://springrts.com/mantis/view.php?id=2673