BUG] Persephone fails to recognize tracks labeled A1, A2, B1, B2 (e.g., vinyl-style enumeration)

Persephone does not detect or display tracks that are enumerated using vinyl-style track numbering (e.g., A1, A2, B1, B2) as commonly seen in ripped vinyl releases or files tagged with tools like Mp3tag. These tracks are otherwise valid and playable in other MPD clients and in Persephone in sidebar as well (but not album view) when queued using other MPD client.
