CMake is building 32-bit build even when executed from "Visual Studio 2015 x64 native Tools" command prompt. I'd to do following to get 64-bit build. It might be nice to include this in documentation.

1. Go to "Visual Studio 2015 x64 native Tools" command prompt. Make sure you have VS2015 Update 3.
2. cmake -G"Visual Studio 14 2015 Win64" ..
3. cmake --build .

This will generate Debug build. To get the release build do cmake --build . --config Release.