Created delete_policy

Created a policy_delete command.  Nodes now have a 'bound' field in the
database that in the absense of a policy associated with the node will
force a noop installer causing a local boot.  An unbind will now clear
any policy and set bound to false.
Augment Node Views

Augmenting node views.  Node summary view will show hostname and IP
address to assist with identifying a specific node in the list. The
detail view of a specific node will show the bound statis as well as the
policy assuming it has noe been removed.  If it has a message to that
effect will show in place of the policy.
Add Bound Field To Nodes

Adding a version 4 to the DB migration scripts that implements the bound
field.  If a node has a policy, the bound field will be set to true,
other wise the column default is false.
Implementing pull request feedback

   * Hard-coded an installer for nodes that are bound without a policy.
   * Added DB constraint forcing nodes with a policy to be bound.
   * Removed a redundant method on Razor::Data::Policy
   * Removed changes to node view to be put into a new pull request.
   * If a node has no policy but is bound.  The Policy key is simply
     absent from the node view.
   * Fixed test spec files to accomodate changes.
   * Fixed a couple of code readability issues.
   * Updated API docs.