DigitalInputChange class does not work when initialised with FALLING

[avanlievenoogen]

When the object is initialised with FALLING, the triggered_ member is only set with a falling signal because only then the ISR is called. As the routine during tick(), checks for a changed output, this check always fails as the _lastoutput is never made high again. And as such the handler attached to the digitalInput is never called. I would think this check should only take place when you initialised the object with CHANGE.