alcotest

Set min version of cmdliner to 1.1.1 cmdliner.1.1.1 removed trailing whitespace from help messages. Building this with cmdliner < 1.1.1 causes the comparison with alcotest-help.txt to fail due to whitespace differences.

Update contributing and help generation

Allow overriding the number of columns with ALCOTEST_COLUMNS env var

Fix a crash when running parallel 'checks' in multicore Multiple domains were using the same Formatter to output data, this is not mpsafe. Fix it by making sure each Domain uses its own Formatter and include shims for backward 4.x compatibility.

Allow overriding the number of columns with ALCOTEST_COLUMNS env var