1. Refactored "CustomNodeManager.GetDefinitionFromPath" and "DynamoModel.OpenWorkspace" methods.
2. Added "Dynamo.Nodes.Utilities.PreprocessTypeName" method to preprocess type names coming from older DYN files.
3. Added "Dynamo.Nodes.Utilities.ResolveType" method to help resolving type given its fully qualified name.
4. Added 15 test cases to fully test these two new utility methods.
5. Added "UtilitiesTest.cs" file to "DynamoCoreTests.csproj" project.