Bug in in array_processing, modul get_spoint

In modul get_spoint, `spoint[i]` (unit is sample) is set to a variable with unit time. I think instead it must be:

        ...
        #diffstart = (slatest - stream[i].stats.starttime)
        diffstart = (slatest - stream[i].stats.starttime) / stream[i].stats.delta
        frac, ddummy = math.modf(diffstart)
        spoint[i] = int(ddummy)
        ...

 Same for epoint:

       ...
        #diffend = stream[i].stats.endtime - eearliest
        diffend = stream[i].stats.endtime - eearliest / stream[i].stats.delta
        frac, ddummy = math.modf(diffend)
        epoint[i] = int(ddummy)
        ...
       
If the start time of all traces are the same, then this bug does not have an effect.