I got around this by creating a new project in Visual Studio 2017:
New Project > JavaScript > Windows Universal > Blank App (Universal Windows)
Then export from C2 Windows Store - Windows 10, VS 2015.
Open the folder with the exported files.
Copy and paste everything from the export folder into the root of the new VS 2017 project EXCLUDING:
package.appxmanifest
the .jsproj file
the .sln file
Seems to run okay, although I didn't do any extensive testing.