Visualize DSRevitNodes.ReferencePoint
Add comment for implementing IGraphicItem interface for ReferencePoint
Remove dead code in DynamoLoader.LoadBuiltInTypes() as ASM libraries will not be loaded
Add a property group so that MSBuild is able to build Dynamo with FScheme engine
Add category "DSExecution" for all test cases require DS engine
Fix naming convention for shortName to start with lowercase
Add basic element binding functionality method

need to add support for serialising and deserialising the Ids
Update the Element Binder so that it pulls the correct data out of the trace mechanism

And binds to it.

There is an outstanding TODO: to handle the interaction between ElementId and GUID ID correctly
Add basic use of trace within Reference Point
Removal of unneeded import
element selection ui node sample
moved nodeimpl for selectelement sample
renamed ElementValidity to ElementUtils
Resolve merge conficts
Fix build error caused by file renaming (ElementValidity.cs -> ElementUtils.cs)
Merge pull request #667 from ke-yu/ChocoButter

Visualize DSRevitNode.ReferencePoint
Merge branch 'ChocoButter' of https://github.com/Benglin/Dynamo into ChocoButter