added more explanatory text and examples to README
added more explanatory text and examples to README

MullinsLab/sickle,ucdavis-bioinformatics/sickle,biorelated/sickle,MullinsLab/sickle,najoshi/sickle,kdmurray91/sickle,jdidion/sickle,MullinsLab/sickle,FabianFrancoRoldan/sickle