Add ref name renaming for synteny datasets

[cmdcolin]

Currently the PAFAdapter does not return results from getRefNames so is unable to render synteny on ref-name renamed datasets

[cmdcolin]

Note that this might mean that getRefNames should submit an assembly name to the opts argument so that it can return the right refnames. Most adapters wouldn't need to care but the PAFAdapter might want to handle this

[cmdcolin]

This was seen trying to open a PAF file that used human vs human genome assemblies with mashmap where i used a hg19 with chr prefixes while ours doesn't include chr prefixes https://gist.github.com/cmdcolin/f9f0c1c61b7c840475c1815a7a607239