remove a group-induced requires loop uncovered by https://github.com/dalehenrich/metacello-work/issues/295
Issue #39: add CI group and XMLSupport-Tests, 'Gofer-Tests', 'Grease-Tests' ... XMLSupport now references #stable version from http://www.squeaksource.com/XMLSupport
load CI group now so that we can include tests for XMLSupport, Gofer and Grease