Recognize leading articles for the Esperanto language when auto-generating title sorts.  Fixes #1336639 [Esperanto alphabetization](https://bugs.launchpad.net/calibre/+bug/1336639)
When reading metadata from file names, allow setting the comments field as well, in addition to title/authros/publisher/series/etc. Fixes #1332582 [some add book regexp bugs and suggestion](https://bugs.launchpad.net/calibre/+bug/1332582)
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