JoinedInput#gets returned String always ends with a newline
formatter adding possibility to append anything to the final version of the 'compiled' psalm text
make --append and --output-append work
fix an error emerging on psalms with appended content
make --dashes work
remove an unimplementable legacy option

psalmpreprocessor handled input in a much more agnostic way; pslm.rb expects more and thus it
won't support option which counted with very rough 'input format agnosticism'