Compose                 Compose an arbitrary number of functions.
Curry                   Pre-specify a procedures named parameters,
                        returning a new procedure.
CurryL                  Lazy curry; thanks, Jamie!
                        <https://github.com/klutometis/R-functional/issues/1>
Identity                Identity function.
Negate                  Negate a function; borrowed from
                        src/library/base/R/funprog.R for pre-2.7 Rs.
Swap                    Thanks, Gabor; see
                        <http://stackoverflow.com/a/23726989>: swaps
                        the first two arguments in a function.
multi.argument.Compose
                        Composition with multiple arguments.
