Added asserts enforcing data type when splitting
Added asserts enforcing data type when splitting

MG-RAST/kmerspectrumanalyzer,wltrimbl/kmerspectrumanalyzer,wltrimbl/kmerspectrumanalyzer,MG-RAST/kmerspectrumanalyzer,wltrimbl/kmerspectrumanalyzer,MG-RAST/kmerspectrumanalyzer