Remove tab characters in download messages
Update CHANGES (pin defaults to git when available)
Workaround some solver scripts: run check with closed stdin
Bump beta version number to 4
Merge pull request #1586 from OCamlPro/fix-solver-script-check

Workaround some solver scripts: run check with closed stdin
Merge pull request #1588 from OCamlPro/beta4

Bump beta version number to 4
Make sure to clean stale files on http download

Should fix #1585