color table and various fixes

- use the actual color table in tagtype json for rendering images (until now, that color table was ignored)
- added proper ordered dithering (works with all colors now, not just gray and pink)
- on the static image content card, you can now choose floyd-steinberg or ordered dithering (or turn dithering off)
- added ÅÄÖ to twcondensed20 font
- small bugfixes
- fix serial passthrough via UART in OEPL-flasher.py

miscellaneous/render_bitmapfonts/render_bitmapfonts.pde

@@ -56,7 +56,7 @@ void setup() {
 
   String str = "!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_abcdefghijklmnopqrstuvwxyz{|}~°ÄÅÆÖØÚÜßáäåæéíöøúüýąČěľłńŘřŚŠź";
   char[] charsetbasic = str.toCharArray();
-  str = "ACDEFHIJLMNOPRSTUVWZiortzÁØÚČŚŠ0123456789-";
+  str = "ACDEFHIJLMNOPRSTUVWZiortzÁÅÄÖØÚČŚŠ0123456789-";
   char[] charsetdaynames = str.toCharArray();
   str = "0123456789.°-";
   char[] charsetnumbers = str.toCharArray();