Reproducible on 4.6.0f1, 4.6.1f1, 4.6.3f1;

Visual Studio solution created by Unity after the Windows Store Universal 8.1 build from Unity has incorrect PreBuildEvent scripts for both Windows and WinPhone projects.

We have 3 plugin dlls located in Plugins/Metro/WindowsPhone81 for WindowsPhone8.1, and dlls with same name for Windows Store located in Plugins/Metro. If we build for Universal 8.1 Windows Store to an empty folder, generated solution doesn't compile unless we fix the PreBuildEvent script for both Windows Store and Windows Phone projects in the solution.

For the Windows Store, because the dlls doesn't get copied to the Unprocessed folder, its missing the scripts that copies the dlls from Plugins/Metro to $(ProjectDir).

And for Windows Phone, it did copy the dlls, but when running AssemblyConverter, it's missing the dlls that was located in the Plugins/Metro/WindowsPhone81

Workaround:
You can check the solution located in WindowsUniversal for the correct modified PreBuildEvent script that actually works.

Repro steps:
1. Open project "case_672630-MODIFIED REPRO.zip";
2. Build for WindowsStore select Universal 8.1 SDK;
3. Output to a clean/empty folder;
4. Open up the visual studio solution generated by Unity;
5. Build the solution and it will fail;