Update VirtualBox (and implicitly VirtualBox Guest Additions) to 4.3.6 and Oracle VM VirtualBox Extension Pack to 91406
Follow renaming of services.xserver.videoDrivers to services.mesa.videoDrivers for VirtualBox Guest
Add "vboxsf" to the kernel modules for VirtualBox Guest Additions 4.3.6
Update Virtualbox and Guest Additions to 4.3.8, Oracle Extensions to 92456
Merge branch 'virtualbox' of git://github.com/Calrama/nixpkgs

Update VirtualBox (and implicitly VirtualBox Guest Additions) to 4.3.6
and Oracle VM VirtualBox Extension Pack to 91406

Conflicts due to minor upgrade in the mean time

Conflicts:
	nixos/modules/virtualisation/virtualbox-guest.nix
	pkgs/applications/virtualization/virtualbox/default.nix
	pkgs/applications/virtualization/virtualbox/guest-additions/default.nix