fix derivitive family removal and add counter
fix derivitive family removal and add counter

loeblab/Duplex-Sequencing,loeblab/Duplex-Sequencing,mwschmit/Duplex-Sequencing,raj76/Duplex-Sequencing,raj76/Duplex-Sequencing,mwschmit/Duplex-Sequencing,raj76/Duplex-Sequencing,loeblab/Duplex-Sequencing