add(coreos-base/oem-gce): Add support for ssh keys on GCE
fix(coreos-base/oem-gce): Drop debug echo
Merge pull request #269 from marineam/gce

add(coreos-base/oem-gce): Add support for ssh keys on GCE
feat(coreos/base): accept keywords on docker 0.7

we want docker 0.7, accept it's unstable nature
feat(coreos/base): add lvm thin
feat(coreos-devel/sdk-depends): add boost-build

building boost requires that the SDK has the b2 command line utility
installed in /usr/bin/b2. Install this utility in the sdk.
feat(accept_keywords): boost build is needed by lvm