Moar hashing stuff

This time with less conflicts and a new file!
doc(config): Fill in missing config options
fix(README): cleanup the README a bit

Improves the README a bit by using more specific and enabling language.
feat(etcd): Write etcd systemd snippet
feat(write_files): Set default permissions to 0644

Fix #26
fix(write_files): Create directories with mode 0755

Fix #28
refactor(*): Break apart packages
fix(etcd): Place etcd.service drop-in in /run
feat(etcd): Default etcd name to /etc/machine-id
feat(etcd): Fall back to hostname if no machine-id
fix(system): Use os.Hostname
fix(etcd): Transform DISCOVERY_URL to DISCOVERY
feat(ignore-failure): add ignore failure flag, fixes #36
feat(github): add coreos-ssh-import-github user attribute
refactor(docs): rearrange order and add full example
chore(release): Bump version to v0.2.0
chore(release): Bump version to v0.2.0+git
doc(etcd): Update etcd docs
fix(fleet): Drop coreos.fleet from cloud-config
feat(unit.command): Add command field to units