2.3.7
• CalculateDefaultLineHeight is not really used
• Use layout fragment/selection heights instead of typingLineHeight; deprecate it
• Fix extra-line metrics via extraLineFragmentAttributes (Simplify the FB15131180 workaround)
• Use ceil for default line height and remove implicit stTypographicBounds var
• Add secondary editor window on launch; rename/refactor primary VC; extract attachments
• Remove unused lastViewportBounds tracking in STTextView
• Suppress relayout when viewport is vertically contained; add upward prep band