Request: add a flag to get ddbg_gdb behavior

[Bill Baxter]

Renaming the exe to get different behavior is a neat trick, and I know 
it is relatively common in the Unix world.  It makes sense there because 
symlinks are rock solid.  However, in Windows it means I have to make a 
copy of the exe every time I upgrade ddbg.  I'm not worried about the 
tiny bit of disk space the extra copy uses, but just the annoyance 
factor.  Anyway, I see no real advantage to typing 'ddbg_gdb' vs 'ddbg 
-gdb'.

I think there was also one person who accidentally re-named ddbg as 
ddgb_dbg or something like that, and couldn't figure out why the 
integration with Code::Blocks wasn't working.  If that were a flag the 
program could raise an error saying '-dbg is not a recognized flag'. 
But it would be a bad idea to raise an error about the program name 
itself not being what you expected.

--bb