script to pre-build all commits in a git-bisect, and use them during testing

[Britton Kerin <britton.kerin@gmail.com>]

Problem: it's annoying to have to build each commit when
git-bisect'ing for something that isn't being tested automatically (so
no git bisect run).

Solution: https://github.com/bkerin/git-batch-bisect

It has an interface almost exactly like native git-bisect so it's
super easy to learn but it handles a couple additional commands to
create worktrees for all the commits, parallel build, and test in
them.

From the README:

     git batch-bisect start bad_commit good_commit
     git batch-bisect runinall 'autoreconf --install && ./configure && make'
     git batch-bisect runincurrent ./test_program
     git batch-bisect good
     git batch-bisect runincurrent ./test_program
     git batch-bisect bad
     # etc.

I'd be grateful for any feedback on this script.  I don't actually
bisect all that often, so it's only tested on one real-world project
so far.  I thought it might live in contrib someday if it's useful to
anyone else.

Britton