I thought I needed it for Commit::parent_count(); turns out that I
didn't, but since I've tested the update anyway I thought I'd include it.
I had to delete Cargo.lock and let cargo regenerate it, since otherwise
I got an error that I think was fixed in a newer bitflags version:
https://github.com/bitflags/bitflags/pull/165
No particular reason for the switch, I tried it when I got a bunch of
errors related to bitflags when upgrading git2 (see the following
commits). Turned out they were not related to the edition used, but
there's no reason not to switch anyway, is there?
This requires Rust 1.31 (from last year) to build.
the features use a lot of native libs that are tricky to compile
(especially now that the openssl-sys crate is unmaintained and depends
on an outdated version of the openssl c library) and this tool doesn't
even use any of them. the build is easier if we just turn them all off
i believe that, due to this bump, we need at least rust 1.26 to build
git-absorb
