Add reset/zero function to IIR/FIR Filter

The IIR/FIR filter classes are extremely helpful for the project I am working on, however, I am working with a very slow filter on a sensor that sometimes I want to pick and place somewhere else. It would be extremely convenient to be able to reset/zero the filter so I don't have to wait for the slow transients to settle when I know there has been a substantial change in environment 