Merge pull request #94 from PascalSchumacher/GROOVY-5868

GROOVY-5868 - ConfigObject is unexpectedly no longer Cloneable
merged
Merge branch 'GROOVY_1_8_X' of https://github.com/groovy/groovy-core into GROOVY_1_8_X
Added unit tests showing that GC'ed SoftReferences are not cleanup from memoize caches
Fixed cache's SoftReferences instantiation in order to register them in a ReferenceQueue
deactivated tests because they are successful only sometimes on the build server
minor refactor
Fix missing class in test case