add test case for migration class
Added migration functions

- CoordinateSystem transformations (after being added back to
ProtoGeometry.dll)
- Family type, wall and floor selectors
- Added a migration helper function to change both node name/type and
node nickname
fix bugs
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
fix the bug at the string concat
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
change the math.average
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
fix the bug in slice list node
Added migration functions

and updated NodeMigration attributes
change some test cases' parameters
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Added dummy nodes for DynamoRevit migration
Added dummy nodes for DynamoCore migration
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
Merge pull request #28 from ellensi/CrossFade

CrossFade is going into CB2b1, so I'm merging this in to get more accurate NUnit results.
Merge pull request #30 from Zhengzi/CrossFade

Merging this now with the understanding that the comment will be addressed immediately after this.