title: List custom fonts in tesseract-ocr/langdata/font_properties?
body: <p>I am using <code>Tesseract 4.0.0-beta.1-370-g8b64</code> on <code>Ubuntu 16.04</code> by building it from source. I've got a directory of font files, and it seems from the <a href="https://github.com/tesseract-ocr/tesseract/wiki/Fonts" rel="nofollow noreferrer">documentation for fonts</a> that you need to list the custom fonts in <code>training/language_specific.sh</code> and <code>langdata/font_properties</code>. Also it seems that fonts are listed in <code>font_properties</code> in some particular format, however I can't find the format anywhere. Is there any link or instruction asking how to do it? </p>