Allow associating a font to each of the generic
font-family names.
Bump crengine:
- CSS parsing: accept (and ignore) namesspaces
- isImage(): more checks for <object> as it can have inner content
- getFontFileNameAndFaceIndex(): returns if font has math support
- getFontFileNameAndFaceIndex(): returns if font has emojis
- CSS/Fonts: add support for font-family to font name mapping