Fixes #450

Nearly the last stage of source all components to containers.
Kubectl will be called from hyperkube image.

Remaining tasks:
 * Move kube_version variable to kubernetes/preinstall
 * Drop placeholder download.nothing requirement

kubelet via docker
kube-apiserver as a static pod

Fixed etcd service start to be more tolerant of slow start.

Workaround for kube_version to stay in download role, but not
download an files by creating a new "nothing" download entry.

Improves upgradability of calicoctl by leveraging docker tags.

This should make things a little more composable,
by making these roles meta roles that perform no
actions by default we allow each role to own its own
resources.

using a shared folder can cause race conditions for the download
role as it tries to download files on all the nodes to the same
shared path.  This adds a flag to run the tasks in the download
role on just one node.

reorder master handlers

typo for sysvinit

fix etcd configuration for nodes

fix wrong calico checksums

using a var name etcd_bin_dir

fix etcd handlers for sysvinit

using a var name etcd_bin_dir

sysvinit script

review etcd configuration

install docker on a largest number of linux distribution (based on https://github.com/marklee77/ansible-role-docker)