Added function to module Data.Nat 	modified:   libs/contrib/Data/Nat/Difference.idr
Added function to module Data.Nat
	modified:   libs/contrib/Data/Nat/Difference.idr

kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev