fix(app-emulation/qemu): Remove unused architectures.

We don't have any arm or i386 targets right now so they can go away.
feat(sys-kernel/coreos-kernel): Add 9P virtio fs support.

This allows qemu virtual machines to access plain directories on the
host system in addition to the usual disk/filesystem images.
feat(coreos-base/coreos-base): Add default vimrc so vim acts like vim.

Because, I mean, really.
fix(sys-kernel/coreos-kernel): Fix virtfs+dbus, add PCI hotplug.

This adds the following patch: (sent upstream, waiting on response)
  "9p: send uevent after adding/removing mount_tag attribute"

Also enable PCI hotplug to take advantage of more qemu fun! Now
adding/removing virtio devices (which are represented as PCI devices)
at runtime via the qemu monitor console works.
fix(dev-db/etcd): Remove coreos-c10n, it is moving to coreos-init
bump(coreos-base/coreos-init): Update to latest init code, includes c10n

Biggest diff here: coreos-init has a Makefile that supports the usual
'install' and 'test' targets so no file copying is required now.
coreos-c10n has moved to init from etcd and has its own service now.
This version of init also includes support for automounting virtfs
filesystems under qemu for use with an updated version of c10n but for
now c10n remains unchanged. Optionally unit tests are available too!
bump(coreos-base/coreos-init): Replaces oem-services in a generic way.

coreos-detect-virt has moved from oem-service and the oem-service unit
has been replaced by new units that work for both oem and virtfs mounts.
Merge pull request #157 from marineam/virtfs

coreos-init takes over the world