DEVEX-1033 Limit aria2c connections to <= 16 per server for symlink downloads (#473)
DEVEX-1033 Limit aria2c connections to <= 16 per server for symlink downloads (#473)

* Limit aria2c connections to <= 16 per server for symlink downloads
dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit