Add additional | operator for table-style mapping with World injection

[inamiy]

By #26 , table-style mapping becomes hard to inject World, so this PR adds extra func | to resolve the issue.

Example

Previously:

        /// Sends `.loginOK` after delay, simulating async work during `.loggingIn`.
        let loginOKEffect = Effect<S>(queue: .request) { world in
            Just(StateDiagram.Input.loginOK)
                .delay(for: world.simulatedAsyncWorkDelay, scheduler: world.scheduler)
        }

        /// Sends `.logoutOK` after delay, simulating async work during `.loggingOut`.
        let logoutOKEffect = Effect<S>(queue: .request) { world in
            Just(StateDiagram.Input.logoutOK)
                .delay(for: world.simulatedAsyncWorkDelay, scheduler: world.scheduler)
        }

        let canForceLogout: (State) -> Bool = [.loggingIn, .loggedIn].contains

        let mappings: [StateDiagram.EffectMapping<S>] = [
            .login    | .loggedOut  => .loggingIn  | loginOKEffect,
            .loginOK  | .loggingIn  => .loggedIn   | .empty,
            .logout   | .loggedIn   => .loggingOut | logoutOKEffect,
            .logoutOK | .loggingOut => .loggedOut  | .empty,

            .forceLogout | canForceLogout => .loggingOut | logoutOKEffect
        ]

This PR will allow to define closure-style Effect as follows:

        /// Sends `.loginOK` after delay, simulating async work during `.loggingIn`.
        let loginOKEffect = { (world: World<S>) -> Effect in
            Just(StateDiagram.Input.loginOK)
                .delay(for: world.simulatedAsyncWorkDelay, scheduler: world.scheduler)
                .toEffect(queue: .request)
        }

        /// Sends `.logoutOK` after delay, simulating async work during `.loggingOut`.
        let logoutOKEffect = { (world: World<S>) -> Effect in
            Just(StateDiagram.Input.logoutOK)
                .delay(for: world.simulatedAsyncWorkDelay, scheduler: world.scheduler)
                .toEffect(queue: .request)
        }