Renamed the function 'adjustExpander()' to '_adjustExpander()'.
Renamed the function 'adjustExpanderIfNecessary()' to '_adjustExpanderIfNecessary()'.
Moved the logic for determining page height into separate function '_getPageHeight()'.
Renamed variable 'heightBodyLast' to 'heightPageLast'.
Accounting for margins on the <html> element.
Renamed the function '_convertMargin(...)' to '_toNum(...)'.
Accounting for <html> paddings too.
Listening for all subtree modified events from the whole DOM tree.