User should be able to know which reference genome was used in a VCF file

[jaclynperrone]

Is there a way to state what version of the reference genome a VCF file is using to make its comparison? Two questions:

1. Does this meta data exist in a VCF?
2. Is this something that Guacamole can surface when it generates a VCF?

(cc: @arahuja )

[ihodes]

We previously had a field on runs that tracked the reference genome used; I took it out for now as

1. it wasn't being used;
2. the VCF should have a field (##reference=file:///seq/references/1000GenomesPilot-NCBI36.fasta e.g., from the 4.2 VCF spec) tracking the reference. We should surface it, though, and do not currently!

[jaclynperrone]

Yes, let's surface it!

[armish]

Once #820 is merged, we can easily start showing the release field on the examine page.