updated searching for datasets by chromosome to use dataset->has_chromosome sub to increase performance
updated searching for datasets by chromosome to use dataset->has_chromosome sub to increase performance

LyonsLab/coge,asherkhb/coge,LyonsLab/coge,asherkhb/coge,LyonsLab/coge,LyonsLab/coge,LyonsLab/coge,LyonsLab/coge,asherkhb/coge,asherkhb/coge,asherkhb/coge,asherkhb/coge,LyonsLab/coge,LyonsLab/coge,LyonsLab/coge,asherkhb/coge,asherkhb/coge,asherkhb/coge