Calibre support embedding fonts, but this seems redundant (and a space hog) for many devices that have the provision to use Device (system) fonts
(only provide support for CSS, Font declarations)
When sending to device:
1) Query CSS for @Font callouts
2) Add the FONT (if needed) to Device Font folder <move from the book?>
3) adjust the CSS font SRC as needed
4) remove the embedded font
send skinnier book
