interactive mode: print '\n' in sigint_handler, this flush stdout thus ensure color reset. (#283)

main.cpp

@@ -747,6 +747,7 @@ static bool is_interacting = false;
 #if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__)) || defined (_WIN32)
 void sigint_handler(int signo) {
     printf(ANSI_COLOR_RESET);
+    printf("\n"); // this also force flush stdout.
     if (signo == SIGINT) {
         if (!is_interacting) {
             is_interacting=true;