WinHugs, prettier file listings

Hi, On WinHugs, when you get a listing of all files loaded, each file is pretty long. Most of it corresponds to either the {Hugs} prefix, or the current directory prefix. This adds no useful information. This patch makes the listing replace the prefix with {Hugs} or . if it can safely. It also fixes up the editor loading to add this information back in. It also abstracts the filename outputting for Windows, instead of going down WinHugsHyperlink (which was a little bit unclean). Thanks Neil