removed the old Registry.Build() method, replaced with an extension method, making all construction go through PluginGraphBuilder
moved a lot of PluginGraph.Seal() into PluginGraphBuilder
added the new projects for the legacy attributes
ripped the old goofy [PluginFamily]/[Pluggable] attributes out of the main assembly
removed the clumsy IPluginGraph.AddType() method
removing the plugged types list from PluginGraph
eliminated the old PluginFamilyCollection
verified that IsInNamespace with anonymous type is fixed.  Closes GH-7
verified that GH-10 is closed
put a test in for the get all instances bug
Reduction of ObjectFactory footprint (closes #53)
- Kept Container and basic GetInstance methods for convenience
- Rewritten tests to access ObjFac.Container
- Removed DefaultProfile from IInitializationExpression and a related test
  because nobody seemed to use the getter internally and the property is
  defined on an interface that the user doesn't touch a lot.
- Slight ugliness in DoctorRunner making a cast to PluginGraph