Feature Request: Allow user to import yomichan format dictionaries

[quietmansoath]

I already have a bunch of yomichan formatted json dictionaries for use with Migaku for Japanese. They are files I have edited myself or have found online. I would really like to use your app but I can't because there's no way to convert these dictionaries back to EPWING, or, in some cases, it's not possible. Please consider adding this.