Extend font, add some Emoji

[Kater--S]

Add some Emoji and maybe other special character glyphs to the built-in font. There's a HTML-based font editor provided in the repo.

[Kater--S]

Since MarQueTT[ino] does understand UTF-8, there's no problem transmitting Emoji to it. But we will have to find appropriate codepoints in the internal font array which is loosely based on ISO Latin-1 / Windows CP-1252. At least the common accented characters should remain reserved for their regular use.