remove(app-emulation/xen-tools): Remove unused xen-tools ebuild.
add(app-emulation/xenstore): Add minimal xenstore package
feat(coreos-base/coreos): Add xenstore to base images.

Needed for rackspace but would be useful on other Xen systems too.
The utility is super tiny.
Merge pull request #539 from marineam/xenstore

Xenstore