[update 2.0] #20301

2.0.20301
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The following changes have been integrated:

Issue  6728:   infinite recursion on startup preferences.
               http://code.google.com/p/pharo/issues/detail?id=6728

Issue  6723:   Improve Collection Streaming
               http://code.google.com/p/pharo/issues/detail?id=6723

Issue  6715:   RPackageSet is not backwards compatible
               http://code.google.com/p/pharo/issues/detail?id=6715