Added Numeric#duration and changed Numeric#method_missing to make calls to Numeric#duration
Added Numeric#duration and changed Numeric#method_missing to make calls to Numeric#duration

git-svn-id: f957b6bb0c2d31e3f51e2790ed4490abf77c0f52@15 fed8fec5-6314-0410-9670-8f8ba00fed7e

blaxter/duration,blaxter/duration