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
Get Element Id and Unique Id on AbstractElement, add ApproximateAssertExtensions for comparing XYZ, Vector, Point approximately
Refactor Domain and Domain2D into Revit.Geometry namepsace, renamed DSCategory just to Category
Move Category node into Revit.Application
On second thought, let's put in Revit.Elements
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
change from 0.7.xxx to 0.6.xxx
Merge branch 'CrossFade' of https://github.com/Benglin/Dynamo into CrossFade
fix the bug in slice list node
Add test cases for defect MAGN-747
Added migration functions

and updated NodeMigration attributes
Mark unmodified graphnodes affected by a function redefinition as dirty instead of re-adding them to the delta list