continued field support

With kind James Rich's help, I've been able to implement the 
continued field support.

Still it need some testing and I'm on a very limited environment. 
Indeed, there is much more to add. I won't be able to do much more 
sadly. In my case, I've been able to create an ActiveX that runs on a 
web page to show the terminal. Quite far from a text-mode app on 
linux but much more ressource hungry. :)

I also added F-key recognization (kinda like "F1"-"F24" becomes a 
button) and cursor displacement with the mouse, but only in my 
version. It would be almost like a cut'n'paste to put it in linux or 
standard win32.

I must warn that the code hasn't been tested on linux. In fact, it 
has been minimally tested. It must be tested by someone else and I 
don't think many people have the time to do this.

So if anyone has interest for this, or to merge in main source tree, 
just send me an email and I'll send a patch (or full source tree) for 
HEAD.

Marc-Antoine Ruel