Merge branch 'ubuntu_18_04' into 'master'

Solved a bug: The current operational mode was not updated for extended register map servos.

See merge request !2

src/dynamixel_motor.cpp

@@ -312,6 +312,7 @@ void CDynamixelMotor::set_control_mode(control_mode mode)
     {
       value=mode;
       this->write_register(this->registers[op_mode],value);
+      this->mode=mode;
     }
     else
     {