Fix thinko in skipping over decoded message samples.

mode_s.c

@@ -2335,8 +2335,13 @@ void detectModeS_oversample(uint16_t *m, uint32_t mlen) {
             }
             
             // Skip this message if we are sure it's fine
+            // (we actually skip to 8 bits before the end of the message,
+            //  because we can often decode two messages that *almost* collide,
+            //  where the preamble of the second message clobbered the last
+            //  few bits of the first message, but the message bits didn't
+            //  overlap)
             if (mm.crcok || mm.correctedbits) {
-                j += (16+msglen)*6/5 - 1;
+                j += (8 + msglen - 8)*12/5 - 1;
             }
             
             // Pass data to the next layer