The attached patch does three things:
* URLs are highlighted (italicised)
* Pointer shape is changed when the pointer is over a URL
* Allows URLs to be launched by double-clicking
The method of URL launch is currently hard-wired to run "x-www-browser" with one argument, the URL. This should really be configurable - but, at least on Debian installations, x-www-browser is a good default.
(Patch is against 0.4.6.)