fix(coreos-base/coreos-dev): Add coreos and gcc as dependencies.

This makes coreos-dev a proper superset of coreos.
add(coreos-devel/board-packages): Target for building binary packages
fix(coreos-base/oem-*): Install OEM packages into /usr/share/oem

The install script no longer sets ROOT to /usr/share/oem so the ebuilds
need to install themselves into the correct path.
Merge pull request #494 from marineam/oem

OEM reorg
feat(iso): add cdrtools for iso building
bump(app-misc/ca-certificates): Update to certs from NSS 3.16

Nothing dramatic, just noticed a new version was available.

Certs changed:

    - "TDC OCES Root CA"
    - "Firmaprofesional Root CA"
    + "TeliaSonera Root CA v1"
    + "E-Tugra Certification Authority"
    + "T-TeleSec GlobalRoot Class 2"
    + "Atos TrustedRoot 2011"
Merge pull request #498 from marineam/certs

bump(app-misc/ca-certificates): Update to certs from NSS 3.16
Merge pull request #497 from polvi/iso

feat(iso): add cdrtools for iso building
feat(coreos-base/coreos): Add ethtool to the base image.

ethtool has long since replaced the old mii-tool as the proper way to
get information on physical ethernet links but we haven't been shipping
it. At some point we should prune some of the old crufty tools like
mii-tool from sys-apps/net-tools and similar.
fix(oem-vagrant): Ignore missing /etc/environment
Merge pull request #500 from marineam/ethtool

feat(coreos-base/coreos): Add ethtool to the base image.
bump(coreos-base/update_engine): Source path reorg.

All of the helper script services and systemd files are included in the
update_engine repository now. The pxe service now uses the more generic
'stub' name. Fix install path for dbus config. Remove useless udev rule.
feat(coreos-base/coreos-cloudinit): Create generic template.

Replace coreos-cloudinit-oem.service by a generic service template that
can be used for any path. Add rule to load cloud-configs installed by
the coreos-install utility.
bump(coreos-base/coreos-init): Update coreos-install script.
Merge pull request #503 from bcwaldon/ignore-missing-env

Ignore missing /etc/environment in Vagrant OEM cloud-config
bump(coreos-base/coretest): Fixes etcd test on clusters
Merge pull request #505 from marineam/coretest

bump(coreos-base/coretest): Fixes etcd test on clusters
remove(dev-lang/python): This moved to portage-stable a while ago.
add(dev-lang/python-oem): create a minimal python for OEM

A number of cloud agents are written in python. Install a basic python
to /usr/share/oem/python with this ebuild.
fix(dev-lang/python-oem): cleanups and fixes for OEM python

Remove all RDEPENDS, OEM packages are installed after prod images are
pruned of the previously installed package database.

Re-enable XML and ctypes support since the required libraries happen to
be bundled with Python.

Assorted other simplifications.