Treat a product file the same way as other build system files...

... when doing change tracking after restoring a build graph.

Changes in one product can influence properties in other products
via the surrounding project.

Change-Id: I4294b326280e676939de9533309fdfa9146f9e92
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Serialize more data.

SourceArtifact::overrideFileTags was missing, as well as
ResolvedProduct::transformers.

Change-Id: I0118b57bcf345c83bba64f2716fac20a91c86a28
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>