build.cmd fails if only F# 4.0/VS 2015 installed

[latkin]

It appears this repo has a hard dependency on FSharp.Core 4.3.1.0 being GACed.

4.3.1.0 is binplaced by VS 2015/F# 4.0, but not added to the GAC. Only the latest (4.4.0.0) is GACed.

If the latest FSharp.Core is not the desired dependency that's fine, but it might be good to document that and/or print a helpful error message during build/test if the required version can't be loaded.

As it stands tests just blow up with

System.IO.FileLoadException: Could not load file or assembly 'FSharp.Core, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'FSharp.Core, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' ---> System.IO.FileLoadException: Could not load file or assembly 'FSharp.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'FSharp.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

[palladin]

Thanks for pointing that out.