Handle NuGet packages with included targets files

[chrischu]

I noticed that NuGetReferenceHintPathRewrites assembly references but does not rewrite the imports and the "EnsureNuGetPackageBuildImports" targets that are generated by NuGet when a NuGet package that contains a ".targets" file is referenced. The following screenshot shows the import/target after referencing the "Fody" NuGet package as an example:

It would be really cool if the references to the target files could be rewritten as well.