With the December 21, 2015 update, the added a Beta connector to R. You can find out more at Visualizing and operationalizing R data in Power BI.
What is amazing, is that there is a very long list of enhancements to the desktop tool. And, especially so, since Desktop is a free tool. Has Microsoft lost it? Or perhaps have they finally decided to once again try to take the lead in BI.
A hidden gem is support to connect to an on-premises SSAS Multi-dimensional database. In earlier versions, only Tabular was supported. And the Navigator connection tool only needs to know the name of the server and the authentication user/pw.
Power BI 2.0 desktop September, 2015 update to read about the upgrade in detail.
Power BI 2.0 desktop December 21, 2015 update to read about the upgrade in detail.
Power BI Get Data Navigator listing the SSAS Multi-dimensional databases
Power BI Relationships Tab - displaying the imported Multi-dimensional table
Power BI Waterfall displaying the imported Multi-dimensional table