This commit updates `virtualbox.sh` post install script for archlinux-x86_64 template to install VirtualBox Guest Additions without X.org requirements. It installs `virtualbox-guest-utils-nox` package instead of `virtualbox-guest-utils`, as the latter package pulls X.org and many other packages as dependencies.
I've changed (would like to change) the ruby versions used in the documentation to reflect a more current ruby version. 1.9.2 refuses to compile at all on the latest version of OS X (Yosemite). I've proposed 2.0.0-p598 because a) I've installed Veewee on an Ubuntu 12.04 machine and my OS X machine within the last 24 hours, and successfully built a box without any noticed ruby errors, and b) I received advice on #774 that seemed confident that 2.0.0 was the correct version supported by Veewee. I've also stuck a h5 at the top of the doc to assert that this is the supported version (though have not included a patch number). (I think it would also be good if the notes regarding v1.8.7 were removed completely but I don't have the information about who's using which versions of ruby).