Get rid of :order for barclamp, deployment, node_role, and role models.

It is replaced with:

 * barclamp:  Extreme late-binding order resolution based on the
 barclamp dependency graph and the name of the barclamps. No extra
 tables were added to instantiate this.
 * role: Late-binding order resolution based on the dependency graph
 implied by the interrelationship between role and role-requires
 tables.
 * node_role:  Explicitly track all the interrelations in a HABTM
 relationship with itself.
 * deployment: Add a parent field instead.
Zap mandatory checking for :order in BDD.
Merge pull request #590 from VictorLowther/pull-req-master-21a84667f0cddaf9b1e0a4c6ed0f99d21682e2c0

+1.  I'll fix the BDD issues (there are unrelated mid flight changes).  Your attempt to fix looks pretty reasonable.