gecko_ia2 virtual buffer: Trim URLs of links with no content

[jteh]

At present, in the gecko_ia2 virtual buffer, if there is a link with no content, the full URL is rendered into the buffer. This is because the code eventually falls back to value if no other text is found. While links with no content are uncommon, they do occur, usually where a style is used to visually represent the link in some other way. Instead of rendering the full URL into the buffer, the URL should be trimmed in the same way as URLs for graphics; i.e. using getNameForURL().

[jteh]

Implementation included in misc deps 2008-06-17-01.