Don't close the stream when caching metadata references
- Keep the stream open until we dispose the metadata itself
- Change the cache to dispose entries if the old value is disposable
Removing dependencies from shared project
Revert "Removing dependencies from shared project"

This reverts commit 6c29dabe3656b6f3a9fafa279355eb3b742ede61.
Ensure outputDir is never null for packing
Reduce number of files in packed output

- Nupkgs, nuspecs and SHA files are not copied to output packages folder
- Only copy assemblies needed by the framework specified with '--runtime'
Code review changes