Revert "Don't sync with C library I/O buffers"

It seems is the cause of strange and rare hangs
reported by some users where Stockfish stops
responding to GUI. It is not clear why but for
the moment revert the patch.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/main.cpp

@@ -35,11 +35,6 @@ extern void kpk_bitbase_init();
 
 int main(int argc, char* argv[]) {
 
-  // Don't sync with C library I/O buffers, faster but now using printf()
-  // or scanf() could yield to issues because buffers are independent.
-  cout.sync_with_stdio(false);
-  cin.sync_with_stdio(false);
-
   cout << engine_info() << endl;
 
   bitboards_init();