gem2rds function converts GEM files into Seurat object structure

"addPloidy" function  takes as input the dapi_dtb file generated by the previous nuclear_feature_cal.py script.
--The parameter "num" represents the DAPI area threshold value for distinguishing between mononuclear diploid and mononuclear tetraploid cells. 
--The output is a dataframe that can be directly used with the AddMetaData function in Seurat. 

