WIDL: use __RPC_FAR attribute for pointers in proxies

[Mike Hearn]

> Yes, because it makes it easier to compare the output of midl and widl. 
>  Additionally, I hope that projects other than Wine can use widl too one 
> day...

Yeah, I'd vote for *not* following the exact output of MIDL in WIDL 
actually.

- MIDL produces code that could compete in the worlds ugliest code
   competition.

- The casts it uses make new versions of gcc cry

- There's a lot of junk in there we probably don't need (stubless proxy
   support etc)

I'd rather we produced clean, easily readable Wine style code rather 
than copying the output of MIDL exactly. The code isn't magic, it should 
not be difficult to simply compare the meaning of the code if we're not 
sure it matches up.

thanks -mike