Add support for other EPWING dictionaries

[mvysny]

Excellent https://github.com/FooSoft/zero-epwing can export epwing data to a sane JSON format. There are font glyphs that need to be translated to unicode, however luckily there's https://github.com/FooSoft/yomichan-import which contains the mappings for various dictionaries: https://github.com/FooSoft/yomichan-import/blob/master/epwing.go

In case of Kenkyusha 研究社　新英和大辞典　第６版, the font seems to be matching what's under "研究社　新和英大辞典　第５版" / wadai.go but this needs to be checked.

I'm attaching a zip file of all glyphs extracted from Kenkyusha, please compare the glyphs to wadai.go and let me know whether everything matches 👍

[mvysny]

kenkyusha_glyphs.zip

Here are the glyphs. There are two fonts: 0 is smaller and 1 is bigger so maybe we should compare against 1. But it wouldn't hurt to compare wadai.go against both font 0 and 1, just to be extra-sure.