raster fonts for jsMath plugin spriteImageFonts

 Rasterized fonts saved in separate image files -- 1 image per font to
 enable viewing of jsMath pages by a web-browser which is missing
 access to TeX fonts. Sprite organization of raster fonts alleviates the
 problem of jsmath-fonts, which is a tremendous number of images since
 each character has a separate image file. But such advantage comes at
 speed and compatibility cost.