Get rid of cmd.exe when radiant starts up

[mfn]

Whenever radiant starts up, a cmd.exe window is shown first and remains throughout the life time of the editor application.

Let's see if we can get rid of it.

[AEonZR]

That was something on my wishlist as well. This console seems to be used for debugging, i.e. shows warnings/errors on editor startup. So it should be possible by #define or something as obvious as that to turn it off.