parsers: lines: display "ignoring (...)" for all unrecognized lines

[rmilecki]

This is very helpful for debugging problems with parsing lines.

[rmilecki]

This addresses:

• No warning with lines #155
• Debugging a template file is too difficult #339

This diff looks quite big, but the real change is if first_line_found is False: → if first_line_found is True: and comment update. The rest of diff lines are whitespace changes (indention level).

To review this pull request easily please use git's option -w or GitHub's setting of "Diff view" called "Hide whitespace"

[rmilecki]

See actual changes in this pull request:

[bosd]

Was afraid this would affect the results.
Tests are still passing, so LGTM