Fix bug where by the YearCache was static when it shouldn't have been.
Fix bug where by the YearCache was static when it shouldn't have been.

nodatime/nodatime,malcolmr/nodatime,zaccharles/nodatime,BenJenkinson/nodatime,malcolmr/nodatime,BenJenkinson/nodatime,nodatime/nodatime,jskeet/nodatime,zaccharles/nodatime,malcolmr/nodatime,zaccharles/nodatime,malcolmr/nodatime,zaccharles/nodatime,zaccharles/nodatime,zaccharles/nodatime,jskeet/nodatime