Update PoliciesExpression to Policy config type

* Add(IConfigurationAction action, string configurationType) and
  Add<T>(Action<T> configure, string configurationType) updated to
  default configurationType to Policy
* Per Jeremy's suggestion https://groups.google.com/d/msg/fubumvc-devel/qb1Uy5ePyWQ/zNFxvYGuEhwJ
Merge pull request #489 from DarthFubuMVC/policiesexpression-defaults

Update PoliciesExpression to Policy config type