Fix tutor7pp scoring to check for negative weight
Fix tutor7pp scoring to check for negative weight

Fix the scoring in tutor7pp so that negative weights are not included.
The fix follows the same scoring method as in egs_chamber. This bug
showed up as a memory leak in the score variable.
ftessier/EGSnrc,marenaud/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,crcrewso/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,nrc-cnrc/EGSnrc,ftessier/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,marenaud/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,marenaud/EGSnrc,ftessier/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,ftessier/EGSnrc,nrc-cnrc/EGSnrc,marenaud/EGSnrc,mchamberland/EGSnrc,MartinMartinov/EGSnrc,mchamberland/EGSnrc,marenaud/EGSnrc,mchamberland/EGSnrc,marenaud/EGSnrc,ftessier/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,MartinMartinov/EGSnrc,mchamberland/EGSnrc,ftessier/EGSnrc