Option to make viper output a bit nicer for reporting viper problems

[pieter-bos]

Some things we should do:

• delete most default names, instead name them in the context:
  • locals typed Int: i, j, ...
  • locals typed Ref: x, y, ...
  • fields: f, g, ...
• maybe imply split-verification-by-procedure?
• maybe imply no-sat?
• additionally (unsoundly) delete functions that are unused and have no termination measure, and unused ADTs (or are they already?)

[bobismijnnaam]

Re: deleting functions: I did some experimentation with that, primarily to expose this to the user with surface syntax, e.g. /*@ focus @*/ public void foo() { ... }, and corresponding ignore for the inverse of that. I think the last version I worked on is on the ast-minimize-2 branch. Luckily it's not that much code, only 500 lines or so, so it might be better to create this from scratch if you're interested.