Puts silo Organization class under Silo class.

Conflicts with Organization class in common.rb which can be included in
a site.
Convert filter.rb classes to using Array().

Code clean-up.
Implements Discovery Connection calls to 1.2 API.

This completes issue #15.
It implements the following calls:
* DiscoveryConnectionListingRequest
* DiscoveryConnectionDeleteRequest
* DiscoveryConnectionCreateRequest
* DiscoveryConnectionUpdateRequest
* DiscoveryConnectionConnectRequest
Enables saving of dynamic sites.

Modifies the Site object to take in the discovery connection and
criteria (optional) which are needed to define a dynamic site.