reverse_correlation_stepfunc_old

  REVERSE_CORRELATION_STEPFUNC - Performs RC between spike times and step function stimulus

  AVG_STIM = REVERSE_CORRELATION_STEPFUNC(SPIKETIMES, STIM_OFFSETS, STIMTIMES, STIM)

    This function performs reverse correlation (AKA the spike triggered average, STA,
    AKA the stimulus that was present (on average) at the time of a spike)
    analysis between a series of spike times and a step function stimulus.

    AVG_STIM is the stimulus that was present (on average) at the time of a spike

        SPIKETIMES is the list of spike times
        STIM_OFFSETS is a list of times relative to the spike at which to 
                   compute the stimulus.
    The stimulus is assumed to be a step function that assumes different
        values at each step.  STIMTIMES is a list of the time of each step,
        and STIM is a matrix of row vectors, where each row corresponds to 
        one stimulus variable.

    See Dayan and Abbott (2005), Chapters 1-2

   See also:  STEPFUNC, DIRRFMODEL_EXAMPLE3