feat(coreos-base/oem-pxe): introduce the PXE oem

simple OEM for PXE. Simply has an oem-release file.
feat(coreos-base/coreos-init): add ssh-key-proc-cmdline

adds the sshkey= feature on the kernel commandline
Merge pull request #172 from philips/pxe-initial

introduce the PXE oem
Merge pull request #181 from gregkh/kernel_update

feat(sys-kernel/x86_64_defconfig) enable EFI in the kernel build
fix(sys-apps/baselayout): Sync baselayout with recent Gentoo updates.

baselayout no longer depends on openrc upstream so remove our
openrc/efunctions use flag and dependency. Depend on efunctions in
coreos-base instead.

Remove os-release and roll back gentoo-release since customizing them is
now handled by the set_lsb_release.
cleanup(sys-apps/baselayout): Remove old functions.sh from baselayout-1
fix(sys-apps/baselayout): Don't install /etc/issue on target systems.

This is handled in /run by coreos-init scripts.
bump(coreos-base/coreos-init): Bump to version with dynamic issue file.
Merge pull request #182 from marineam/ip-issue

IP issue and baselayout cleanup