TRAC #537: make karyotype labels clickable.
TRAC #537: make karyotype labels clickable.

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