Quickfix for NOTHING_TO_OVERRIDE (change method signature).

This implements "Modify method parameters/return type to match one of method in super-classes." solution from https://docs.google.com/document/d/1b9I-7VUMq8As9gd4agU8hPIXrBauplG8_4vLK5Pv-zw/edit#heading=h.6g59oaej69hc 

The code works, but there are few places that look ugly to me (but I haven't been able to find a better way to do this). I've added comments (on github, not in the code) to these places. I'll gladly fix them, but I need guidance how to do this.