Add support for JRiver Media Center

I would like you to consider adding support for jriver media center. JRiver is still under active development and the API rarely undergoes large changes which should ease the support burden.
JRiver is also among the last few media servers with a ten foot interface that supports Direct Show and Mad VR
Here is a link to a description from their homepage https://jriver.com/overview.html

Sorry but this is a really really too small market to be supported in Yatse.