Fix Revit nodes being shown as "Deprecated" on standalone

##### Background
- This fixes [MAGN-2469 Revit nodes shown as deprecated on Standalone](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-2469)
- There is now a way to differentiate between a "Deprecated" node, and an "Unresolved" node
- The notion of "bad nodes" is now irrelevant, all nodes can be loaded from "DYN" or "DYF" files
- Relevant test cases are updated to reflect the latest implementation

##### Preview
The following image shows how unresolved function nodes look like (these Revit nodes cannot be loaded in a standalone Dynamo):
![unresolved-node-types-2](https://cloud.githubusercontent.com/assets/5086849/2564689/68c8b818-b8a6-11e3-8e9d-df1f37265c02.png)