HPRC as a track hub on top of GenArk

[diekhans]

Max suggests that HPRC could be a track hub on top of genark. This would add value with the genark generate tracks and save work by providing BLAT for us.

Some possible problems:

1. Genark will display the NCBI accession, not the sample/haplotype. Max says they should be able to do this.
2. Each genome in GenArk is a single hub. What happens to the hgGateway assembly pull-down menu if we have a track hub with all the HPRC assemblies and we connect to GenArk? Do we still have the HPRC pulldown menu? Switching between the HPRC assemblies this way has a lot of usability value.