re-merge subset cleanup in hashtable.cc
re-merge subset cleanup in hashtable.cc

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