fix(coreos-install): LVM is a third valid lsblk type for coreos-install -d.

Note: You may need to manually use kpartx -d to remove device-mapper
devices after you mount partition 9 and insert your ssh authorized_keys.
remove(coreos-detect-virt): This detect-virt script is now unused.
fix(coreos-install): Update install script for amd64-usr images.
feat(coreos-install): Add option to install a cloud-config file.
fix(coreos-install): Remove pointless check for OEM_ID=pxe
fix(coreos-install): Replace curl with wget.

Support installing CoreOS from limited 'Rescue Mode' environments.
Merge branch 'master' of git://github.com/wtogami/init
Merge pull request #69 from marineam/pxe

Fix coreos-install for /usr images