Update README.md

OB_pipeline/README.md

 # Olfactory bulb (OB) analysis pipeline
 Main scripts:
-1) `cmore_run_reg2template.sh`: registers individual images to the template using MMORF
-2) `cmore_run_warpLabels2Ind.sh`: warps the OB labels back to the individuals
+1) `cmore_run_reg2template.sh`: registers individual images to the template using MMORF and warps masks from template space back to individuals' native spaces
+2) `cmore_segSize.py`: calculates the volume of the masks in individuals' native spaces
 
 MMORF: https://git.fmrib.ox.ac.uk/flange/mmorf_beta