Fixed isShowable function to read minW and minH defined under appConfig.modes.
Looping over the modes will short-circuit first time after isShowable returns true. Assuming height-requirement is met, all modes are showable if 2-page is showable.
Text layout adjustments.
Fixed file modes.
Removed index2 since it was out of date.
Committing content changes.
Updated images.
Cherry-picked comments from staging/dev. Updated screen.sass manually from staging/dev -- screen.css
Somehow missed the updated index file when cherry-picking.
Css fixes to TOC and tabs.
Removed key terms section.
Minor css updates.