Literate: add 2nd include to match NuGet package layout

literate.fsx currently expects the binaries in ../bin/. However, when using it directly from the NuGet package, the binaries are actually in ../lib/net40/.

Suggestion: I've added a second include directive so it works in both situations OOTB. Unfortunately it also causes an FS0211 search-dir not found warning in both (since in either case one of them does not actually exist). Maybe there's a better solution?