inconsistent handling of keywords and conflicts

Various code generators and languages have interesting non-overlapping sets of keywords. Protobuf as a whole does not handle these things consistently (sometimes it mangles them, sometimes it generates code that doesn't compiler). When the mangling causing conflicts with other feels we are one again inconsistent. Then we are sad.

What needs to happen is a systematic push to

1. figure out what we do now
2. propose a unified solution
3. move things to it