Really fix 'opam update' regression (continue 096ca3bac5f4de27ad9c9a846b1ee18c771b694b)
Improve 'opam info' output (and add the ability to see info about non-available packages)
It is now possible to disable some packages on some OS

os: [ !"darwin"]

or

os: ["linux" "bsd"]

This is quite had-hoc at the moment (ie. a typo will not be detected) but it is sufficient to close #260
Improve 'opam switch'

* better 'opam switch list'
* better documentation (this should fix #299)
* add compiler description files (this should fix #305)
update CHANGES to be pandoc friendly
Merge pull request #331 from avsm/patch-2

update CHANGES to be pandoc friendly
Improve 'opam switch list' for system compilers
Update README.md
Update README.md
Update README.md
Update README.md
Update CHANGES to remove pandoc header
Merge pull request #332 from avsm/patch-3

Update CHANGES to remove pandoc header
[new] Adding a darcs backend
[change] Updating OPAM modules to integrate the darcs backend
Merge branch 'master' of https://github.com/OCamlPro/opam into darcs-backend

Conflicts:
	src/client/opamMain.ml
	src/core/opamTypes.ml
Merge branch 'master' of github.com:OCamlPro/opam
Fix installation of packages when some main dependencies are optional (ie. depends: [ ("lwt" | "sqlite3-ocaml") ])

This should fix OCamlPro/opam-repository#235
[fix] Fixing 'darcs fetch' and 'darcs apply' consistency
Merge branch 'master' of https://github.com/OCamlPro/opam into darcs-backend