Fix mavlink disconnection in pauses in cli commands

Implement pause function that proceeds processing mavlink.
Use temporal workaround for simulation, as micros function gives the same result on the same simulation step.

gazebo/flix.h

@@ -37,6 +37,7 @@ void sendMotors();
 bool motorsActive();
 void testMotor(uint8_t n);
 void print(const char* format, ...);
+void pause(float duration);
 void doCommand(String str, bool echo);
 void handleInput();
 void calibrateRC();