Another issue for cleanup review. https://pharo.fogbugz.com/f/cases/13229/Year-arithmetic-broken Ported from Pharo 30. Made a few additional changes to #hash and #printOn: methods that no longer worked, added class comment to AnnualDuration. NOTE: I haven't done a full review on this and the change of seconds from integer to floats can have quite serious implications. Please look at this carefully. Name: SLICE-Issue-13229-Year-arithmetic-broken-MaxLeske.1 Author: MaxLeske Time: 18 September 2014, 9:50:41.500402 pm UUID: 44e5effc-4344-4aec-8cf5-3cb5d92ad73e Ancestors: Dependencies: Kernel-MaxLeske.1827, KernelTests-MaxLeske.678 Port from Pharo 30. - Added class comment to AnnualDuration. - adapted #hash and #printOn: methods that no longer worked because of seconds being floats