[RFC] git-bisect unsure

I'm in the middle of tracking down a bug, unfortunately one of the commits that git-bisect chose had an unrelated problem in it that broke my build. As a result I don't know if this version is good or bad as far as the bug I'm trying to track down is concerned. I would think of a number of situations where one bug could interfere with the testing of another.

My proposal is to add an "unsure" option to git-bisect.

I'm thinking that when you say "git bisect unsure" it would simply shift one commit earlier or later and refrain from ever checking out one marked unsure until there were only "unsure" ones left at which point it would add a disclaimer when you called bad or good and throw up it's hands in frustration if you were to say "unsure" again.

-Kate