Set methods for Builder of an inner class return wrong type

[jsoberg]

Steps to reproduce problem:

1. Create a class (Example)
2. Add a builder to that class (Example.Builder)
3. Add an inner class to Example (InnerExample)
4. Try to generate a builder for InnerExample

What happened:
The set method generated for InnerExample.Builder had a return type of Example.Builder.

Commit: ea8e77c

[jsoberg]

No longer valid since #7 was closed.