From Pharo2, we cannot suspend system events since missing events break the image (rpackage at least should be notified).
Merge pull request #163 from demarey/master

Don't hide events to Pharo during tests...[builds green for non-Pharo-2.0 platforms](https://travis-ci.org/dalehenrich/metacello-work/builds/7359616)
Add asRepositorySpecFor: extension method on FileReference
Remove reference to SystemChangeNotifier.
Merge pull request #164 from demarey/master

Updates for Pharo2 support.
Don't forget to execute the block\!
#assureExistence is not supported in Pharo2. Use a wrapper instead.
Abstract #recursiveDelete.
Abstract #recursiveDelete.
Abstract #recursiveDelete.
Merge pull request #165 from demarey/master

Updates for Pharo2 support.