Migrate Nodes
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Merge pull request #23 from Zhengzi/CrossFade

Migrate Nodes
Implemented "MigrationManager.CreateCodeBlockNodeFrom" method and test cases
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Implemented node migration method for StringInput (to CodeBlockNode)
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade