slowdenoise

  SLOWDENOISE - Remove slow gain changes from spike train
    [RATE, GAIN, T] = SLOWDENOISE(SPIKETIMES, STIMTIMES, STIMIDS, T0, T1, DT, TFILTER, F)

       STIMTIMES - An S x 2 matrix where S is the number of stims,
                and the first column is the onset timet for each stim, and 
                the second column is the offset timet for each stim
       TFILTER - Time resolution of the filter (e.g., 0.1 seconds)