Adding a Star image browser to the top of the page

* Added some extra selector utilities.
* AJAX document transfer can optionally be synchronous.
* Unified link generation logic for text and images.
* Allow image links to point to internal blog pages.
* Added borders around all image-to-image links.
* Added a new image browser widget (code is done but there's not wiki
syntax for it yet, so must use lit tags).
* Added a gallery of the latest Star images to the top of the page.
* A couple new posts.
* Added the WebGL sandbox tool.