Allow sorting by roman numerals in titles

[craigsapp]

When viewing Gomółka's Melodiae na psalterz polski by shelfmark, the works are sorted in original order (since the shelfmark ID includes the order of the works in the source.:

When sorting by Composer or Title, the songs in Melodiae na psalterz polski are sorted alphabetically by the Roman numeral in the title:

It would be more useful to sort the Roman numerals by number and/or exclude them when sorting by title. The Roman numerals in this particular case are ended with a periodd, so the regular expression ^([IVXCM]+)\.\s+ could be used to recognize that the title starts with a Roman number, which can then be either ignored or converted to an Arabic number for sorting.