added include for 'iterator' library
added include for 'iterator' library

Visual Studio 2019 generates a compilation error: "back_inserter is not a member of std" which is resolved by explicitly including the iterator library. For reference >> https://github.com/erengy/anitomy/issues/2
patriciogonzalezvivo/glslViewer,patriciogonzalezvivo/glslViewer