Gentoo: ISO build version bump, use autobuild instead of current-iso
Gentoo: use ssh key auth for root instead of specifying any passwords
Gentoo: better cleanup
Gentoo: configurable kernel version
Gentoo: environ variables should get values from packer ones
Gentoo: use eudev instead of udev
Gentoo: clean packages after world update
Gentoo: few more TCP configuration
Gentoo: add conntrack support
Gentoo: nftables basic setup
Gentoo: update ISO build version to 20141106
Gentoo: update kernel to 3.16.5
Gentoo: wait a bit more for the VM startup