Attach detach disk

* disk provider
   * added attach/detach
   * added whyrun support
   * better error handling to disk create/delete
   * cleaned up needed disk create arguments
   * new disk_attached? and disk_ready? functions
* other changes
   * changed default actions to metadata and tags
   * version bump and maintainer email
I think these "waiting for request to complete" loops should be used if the "wait_for" attribute is set.  That gives the user the ability to fire off a bunch of requests and not block until they're complete.  wdyt?