MAGN-5245 Create UI example node.

http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-5245

PTAL:
- [ ] @lukechurch 

Require Merge:
- [ ] Revit2015
Also if it has to be visible in Dynamo Library we don't need to put this attribute. By default each node is visible in Library.