* Add small 6x8 font with utf8 extended charset.
The font data is created from the CasioNostalgia font by zdimension
found at: https://fontstruct.com/fontstructions/show/1193786/casionostalgia
* Cleanup Font.h
The font data should be untouched.
This commit does:
* whitespace cleanup
* some cosmetic changes to the comments
* removing commas at the end of array declarations
* Update OLED.cpp to use utf8 capable FONT_6x8
* Remove ASCII6x8 from Font.h
Removed because all glyphs from ASCII6x8 are now contained in FONT_6x8.
* Fix char offset for UTF-8 page 0xc3
