Release v0.5.8

• Added support for handling 旧字体 (kyuujitai, old characters) (#604)
• Added support for converting Japanese era years that use a series of digits (e.g. 昭和二〇年) thanks to @SaltfishAmi
• Updated to latest changes to JMDict/JMnedict database (new field types, gloss types, dialects etc.)