bugfix, added last detected trigger to use for binning

Created by: samartse

For some reason the very last trigger event have not been used for binning of pixels into trigger events. There is also strange tome me array slicing have been used [0:-1:], which is equivalent to [:-1], that leads to ignore of last trigger event [-1] from further processing. Exception was thrown, when only two triggers were in array self._triggers of class PacketProcessor in function def find_events_fast(self) .