Enable caching of multiple datasets in one glyphset, so we can draw multi-wiggle tracks
Enable caching of multiple datasets in one glyphset, so we can draw multi-wiggle tracks

Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode