Includes among others:
- (Upstream) Various CHM handling fixes, and others
- HTML documents: rebuild TOC from headings after load
- Font: use metrics for underline offset and thickness
- epub.css, html5.css: tweak ruby styling
- CSS: fix EPUB's head>style content encoding
- CSS: add support for 'box-sizing: content-box/border-box'
- CSS: support for styling the <html> element
Also bump KoboUSBMS to v1.2.2 and FBInk to v1.24.0.
ReaderFont's "Generate font test document": update the
generated HTML so its ToC is build from proper HTML headings.