Added default values to migration

by copying the child elements of the old node, modifying the port index
when needed, and creating new nodes when constant default values are not
applicable.
Added default values to node implementations

- Color.ByARGB
- Solid.Cylinder
- Solid.Sphere
- Solid.Torus
- Solid.BoxByTwoCorners
- Solid.BoxByCenterAndDimensions
- Form.ByLofting
- Excel.WriteDataToExcelWorksheet
append asVector node
Added more default values to migration
Cleanup
append Point.AsVector node during migration
append asVector node
Add Revit unit test helper methods

partially based on the methods in DSEvaluationUnitTest base class.
Add assertions to Sample file test cases

- 01 Create Point
- 02 Ref Grid Sliders
Merge pull request #1555 from Benglin/master

Added user profile links to each in contributor list
Merge pull request #1554 from ellensi/SampleTests

Sample file test cases
Merge pull request #1551 from ellensi/MigrationDefaultValues2

Migrating default values
Merge pull request #1548 from Zhengzi/Maple

append Point.AsVector node during migration