Selective versions resolutions (#68)

* Selective versions resolutions

* orthograph and max line width

* Added a section on non-exact specifications

* clarified the questions about warning

* rewrite with glob patterns as the solution

- added more examples
- added more alternatives and discuss extensions.
- still missing some discussion on the `check` and on `--flat`.
- some open questions

* correct incorrect title

* Incorporate discussed changes + questions

- Clarify retro-compatibility aspects
- Add `--flat` solution according to discussions
- Add `check` command solution based on @bestander comment
- Re-add a new question of `--flat`...

* final changes, no more open questions

Author: victornoel