convertValue2Radian Not clear failure

[yotabits]

dynamixel-workbench/dynamixel_workbench_toolbox/src/dynamixel_workbench_toolbox/dynamixel_workbench.cpp

Line 1227 in 67a1631

if (model_info == NULL) return false;

When the convertValue2Radian method has an error because mode_info is NULL it returns false or 0 which can also a be a valid motor position, I think it could be a good improvement to raise an error instead ! :)