Use IOLoop.current() instead of deprecated instance()

controller/opt/server.py

@@ -34,4 +34,4 @@ if __name__ == '__main__':
     application.listen(os.environ['CONTROLLER_PORT'])
 
     setup_signal_handlers()
-    IOLoop.instance().start()
+    IOLoop.current().start()

solvable/src/event_handler_main.py

@@ -87,7 +87,7 @@ def main():
     ))
 
     setup_signal_handlers()
-    IOLoop.instance().start()
+    IOLoop.current().start()
 
 
 if __name__ == '__main__':

solvable/src/pipe_io_main.py

@@ -26,7 +26,7 @@ def main():
     ))
 
     setup_signal_handlers()
-    IOLoop.instance().start()
+    IOLoop.current().start()
 
 
 if __name__ == '__main__':