Factor index creation from repo collections

Move index generation from OpamRepositoryCommand and OpamState into OpamRepository
Merge pull request #855 from dsheets/repos_index

Factor index creation from repo collections
Merge pull request #854 from samoht/master

more bug fixes
Update doc again
Fix: keep the overlays (and backups) when reinstalling switches
Closes #847
@samoht, still, better before than after !
Merge pull request #856 from AltGr/fix-switch-reinstall

Fix: keep the overlays (and backups) when reinstalling switches Closes #847 @samoht, still, better before than after !
Fix opam version comparison to ignore -beta suffix
Merge pull request #857 from AltGr/opam-version-compare

Fix opam version comparison to ignore -beta suffix
Add doc/release/readme.md
Version 1.1.0-beta
Merge pull request #859 from AltGr/test-beta

Rebuilt config scripts for 1.1.0-beta
Update the release workflow
Update CHANGES
Update shell scripts
Disable bin-annot flag that breaks compilation with ocaml 3.x
ocp-build takes care of enabling it when available anyway
Merge pull request #863 from AltGr/fix-bin-annot-312

Disable bin-annot flag that breaks compilation with ocaml 3.x ocp-build takes care of enabling it when available anyway
Closes #861
Update CHANGES
Merge branch 'master' of github.com:OCamlPro/opam
Colors: make COLOROPAM useful
Merge pull request #867 from raphael-proust/master

Colors: make COLOROPAM useful