added backup hashes every save_frequency files
added backup hashes every save_frequency files

souravsingh/khmer,F1000Research/khmer,F1000Research/khmer,F1000Research/khmer,jas14/khmer,ged-lab/khmer,jas14/khmer,souravsingh/khmer,kdmurray91/khmer,kdmurray91/khmer,ged-lab/khmer,jas14/khmer,souravsingh/khmer,kdmurray91/khmer,ged-lab/khmer,Winterflower/khmer,Winterflower/khmer,Winterflower/khmer