added an option to sum duplicate to ignore zeros
added an option to sum duplicate to ignore zeros

carschno/Mallet,ohjeyong/mallet,lewg/Mallet,zxsted/Mallet,steveash/Mallet,RWArunde/Mallet,lewg/Mallet,carschno/Mallet,zxsted/Mallet,palm-toolkit/Mallet,lewg/Mallet,RWArunde/Mallet,steveash/Mallet,zxsted/Mallet,ohjeyong/mallet,carschno/Mallet,steveash/Mallet,palm-toolkit/Mallet,RWArunde/Mallet,ohjeyong/mallet