reversed order of table
Modified Captioned Images to use displayWidth

- widget-image.js now uses a display width (default 477) to set the image width (less margins), calculates the required scaled height of the image using aspect ratio, and positions the caption below that.  It measures the caption and resizes it's boxes. It then adds up all those heights and gives it back to lastdrawn.  If the hard-set SVG height is shorter than all that, it'll clip.  We need to make the BricLayer respect that newly measured height.
- updated widgets.css to match latest and ever-changing styles from UX
- updated a handful of demo files to have new displayWidth config.
- unit tests, including a square test image.