Fixed --dry-run with some cases of remove
Fixing downgrade of upstream-removed package versions
some cleanup in OpamSolver
(u_packages now already includes u_installed, so some of this was dead code)
experiment: accepting successful unsat responses from aspcud
Merge pull request #844 from AltGr/accept_aspcud_unsat_success

Accept aspcud unsat success
Be a bit less lenient in the pretty-printer

we really want to distinguish between:

    build: [make "install"]

and

    build: [["./configure"] [make]]
Merge branch 'master' of github.com:OCamlPro/opam
Improve the heuristic to handle cases where wish_remove <> [] AND wish_upgrade <> []

This can now happen as we try to uninstall package who disapeared upstream when we upgrade