Currently the APIs for accessing PackageReference information (that is, the VSProject4 and PackageReferences interfaces) operate more-or-less right on top of the project file's XML. This is limiting in that the PackageReference elements will not have been evaluated; for example, if the Version metadata refers to a property such as $(MyCommonVersion) then what a consumer of these interfaces will see is the literal string "$(MyCommonVersion)" rather than the evaluated value.

We should update these interfaces to work on the evaluated data instead.