[enygdkgw] Chess glyphs in Unicode

The existence of chess symbols in Unicode simplifies the task of writing chess software: no need to provide piece images.  It can also allow the user to customize what character to use for each piece on the board, perhaps even permitting letters (of a native language) instead of figurines, which could helpfully matches move notation.

One slight difficulty is that the chess symbols are available in both black and white (as is necessary because they are drawn slightly differently in order to render properly on a white background), but letters are always just black, so need to be rendered in outline for a white letter on a white background.  Also need an outline for black letters on a black background, though maybe avoid coloring dark squares black, instead some lighter color.