.mix files for newer blends

[paarfi]

Could y'all please make available a set of .mix files for some of the newer blends? The files I have go up to R457A and R516A, but I've requests recently to support R472A and R473A. I know we can make those .mix files ourselves, but I feel much better getting official ones from NIST.

[bigoper]

@paarfi
If I may, you can create a PR with these MIX files, and the team at NIST will probably review them.
I think it'll help speed things up :)

[marciahuber]

Hi,
You can send an email to REFPROP@NIST.GOV to request the files. The problem with R473A is that it contains R1132A, and there is not yet a published EOS for it. It should be coming soon but is not yet available. R472A is not a problem.

[bigoper]

@marciahuber you guys are ROCKSTARS!