PR action-required tag, and a Phabricator instance

[Edward Z. Yang]

Hey all,

Two quick reports for Cabal:

1. I've tagged all PRs as either cabal-install/library. This should
help triage, since the nature of patches to these different projects
can be quite different.

2. I've tagged PRs that are KNOWN to not be mergeable (either due to
Travis failure or something pending that needs to be fixed as)
action-required.  PRs that do NOT have this tag are untriaged. Please
look at them and decide if we can merge them or reject them.

3. thoughtpolice set us up a callsign on phabricator.haskell.org
and I added an .arcconfig so we can accept "arc diff"s now too.
I've added Cabal people with Phabricator accounts to it
   https://phabricator.haskell.org/tag/cabal/
If I missed you let me (or someone else who is a member) know.
Don't forget to sign up to hear notifications about any portions
of code you might care about.

Edward