Hopefully fix crashing issues

Chess/nimfish/nimfishpkg/position.nim

@@ -65,6 +65,9 @@ type
         mailbox*: array[Square(0)..Square(63), Piece]
 
 
+proc toFEN*(self: Position): string
+
+
 func inCheck*(self: Position): bool {.inline.} =
     ## Returns if the current side to move is in check
     return self.checkers != 0

Chess/nimfish/nimfishpkg/uci.nim

@@ -357,8 +357,9 @@ proc startUCISession* =
                 of NewGame:
                     session.board = newDefaultChessboard()
                 of Go:
-                    var thread: Thread[tuple[session: UCISession, command: UCICommand]]
-                    createThread(thread, bestMove, (session, cmd))
+                    var thread = new Thread[tuple[session: UCISession, command: UCICommand]]
+                    createThread(thread[], bestMove, (session, cmd))
+                    GcRef(thread)
                 of Stop:
                     session.currentSearch.load().stop()
                 of SetOption: