release-9d8f56c

Adding roles and admin command role permissions (#307)

# Changes
* Config `Roles`
  * rolename => role permissions
  * Permissions can be widely permissive or narrow depending on specificity
* Got rid of old "permission" property on users
* Added a couple of "example" roles.
* User/Admin are immutable. Users have no elevated permissions, admins have all.
* Added `teleport` command.