SEQ for sequencing executions

See #182, release log:

• a494bf6 by @yegor256: Merge pull request #183 from c...
• b24cb1e by @yegor256: #182: typo
• 2d9a6c0 by @yegor256: #182: polished
• 090f12c by @yegor256: #182: tests
• 3e43581 by @yegor256: #182: seq

Released by Rultor 1.69.1, see build log