* For each symbol, add its hex code (0xf641 for the 'Ad' icon, for example) to the *Range* list (or the symbol list when its simple enough) in the `fonts.json` file
* sources - list of file,range(,symbols) wanted (as a dictionary of those)
* bpp - bits per pixel.
* size - size.
* patches - list of extra "patches" to run, either string to file which should be run, or list of arguments (with first one being the command being run)
`navigtion.ttf` is created with the web app [icomoon](https://icomoon.io/app) by importing the svg files from `src/displayapp/icons/navigation/unique` and generating the font. `lv_font_navi_80.json` is a project file for the site, which you can import to add or remove icons.