WIP: AndOrListParser: clear condition after parsing conditional pipeline
WIP: AndOrListParserTest: complete single pipeline test
WIP: AndOrListParser: and-then
WIP: AndOrListParserTest: or-else
WIP: AndOrListParserTest: comment, newline, and line continuation
WIP: AndOrListParserTest: many pipelines
WIP: AndOrListParserTest: single pipeline followed by semicolon
WIP: AndOrListParserTest: single pipeline followed by ampersand
WIP: AndOrListParserTest: single pipeline followed by double semicolon
WIP: AndOrListParserTest: many pipelines followed by ampersand
WIP: AndOrListParser: update comment