Microsoft is in the process of developing the “OneCore”, a universal OS. Andromeda is just one part of the Composable Shell (CShell), the new adaptive shell in Windows 10 which allows the OS to adapt to any device its running on. Andromeda will bring multi-monitor support, a supercharged Action Center and a full-featured taskbar among other things to your device. The technology is still in the process of development and will not be out until the end of 2017.
As a side note, Google is also in the process of developing a universal OS. The codename for the project, ironically, is also Andromeda.
I guess we will see which company will win the race against the universal operating system.