Update NuGet packages.

Updated dependency packages to the latest versions.
Removed unused assemblies.

Remove assemblies that are not used in any tests.
Add ability to re-write InternalVisibleTo

Enhancement #6
InternalsVisibleTo attribute declarations will be rewritten with the
public key of the assembly being referenced. This will occur at the same
time references are fixed for an assembly.
Version bump

Update version numbers for next release.