Mainchat-crashing DC++ 0.797 and 0.799

DC++ 0.800 fixes a bug wherein multiple magnet links in one message causes a crash. To crash DC++ 0.797 and 0.799, send a main chat message with multiple magnet links. It requires no special operator privileges and can cause general disarray fairly easily.

Since DC++ versions prior to 0.790 are vulnerable to several remote crash exploits themselves (for 0.782), only DC++ 0.790 and DC++ 0.801 remain secure. Other versions, including the ever-popular DC++ 0.674, can be crashed by untrusted, remote users.

May improved security ever prevail.