re-center lightbox when resizing browser window
refactor code that gets content size into own method

and also use kwfRoundBorderBox specific code in both cases
improve lightbox responsiveness: resize to max-width of viewport
responsive lightbox: move close button inside lightbox to not waste space
use clientWidth to get max size, excludes scrollbars

and do center logic on our own
no padding in mobile mode
overflow auto lightbox content, allows non-responsive content in the lightbox
improve lightbox responsive
add border to content, so measuring works better
on touch devices ignore resizes, only listen on orientationchange
don't resize if size didn't change
higher limit for mobile version
measure possible size without scrollbars
improve test with larger image
add viewport setting for test, to be able to properly test on mobile devices
optimize lightbox for mobile devices with orientationchange
add manual test for lightbox
don't disable scrolling of page, is problematic on mobile devices
remove commented out code, fix tailing comma error
adapt unit tests