interleave option needs to set p flag
interleave option needs to set p flag

this should fix the bug where random singles appear in paired khmer output
HibberdLab/rnaseq_tools,HibberdLab/rnaseq_tools,Blahah/rnaseq_tools,Blahah/rnaseq_tools,HibberdLab/rnaseq_tools,Blahah/rnaseq_tools