- Image path was hardcoded for a specific machine
        - now use the $NPTOOL env
        - fixing case where rounding in coordinates lead to out of image
          pixel request

        - because of missing libASImage in the ubuntu package

        - allow arbitrary geometry
        - can be used to simulate interstrip and dead layer
        - Use a base class NPImage to manage the image information
        - switch must2 to new scorers
        - fix must2 limitation to event with less particle than
          telescope (issue #17)

        - This caused a crash whan the simulation was not provided a
          physics list option file

        - The Time of arrival of electron was too long
        - fixed the issue by skipping DETransport step going above
          geometrical safety

        - Fixing some bug in DE physics
        - Scorer for counting drift electron

        - Adjustable step length
        - good speed at 1mm step
        - take into account the local field direction