Add assembly redirects for cross version integration tests

[chrisbednarski]

I encountered a few issues before I was able to build V4 and V5 test projects together.

A module merge test will follow, but I thought this might be handy in a separate commit, in case it needs to be undone for some reason later on.

• nuget.config change loads WixToolset.* < v5 from nuget, but uses the local packages from the build folder for the v5 being built.
• assembly redirects are required when a project references other projects with a wildcard (eg. <ProjectReference Include="**\*.wixproj" /> in TestData.proj) and some of those projects are different versions.

Before nuget.config change

Before assembly redirects were added

[barnson]

FYI: This is a topic of some discussion. We need to determine (generally) how extensions are going to work in a mixed v4/v5 scenario. Please let me know if you get blocked by this and we can discuss alternatives (like temporarily committing .msis built with v4).

[chrisbednarski]

Thanks. I should be ok .. I'll skip adding cross-version integration tests until a decision has been made.

[chrisbednarski]

rebased with develop.
This might still provide value, pending your decision on wix versioning strategy.

My two cents:
There seems to be no harm in having this assembly redirect regardless of how the wix versioning will work in the future.