a tiny middleware chainer

Middling is a simple middleware handler in the style of functional composition (chaining really). Middleware is considered any function with this signature:

function (request, response[, next]) { /* ... */ }

• If the last argument is a function, it treated as an asynchronous next signal. (Thus synchronous and asynchronous middleware functions can be mixed).
• The function returned by middling itself has the signature above, so middling chains can be combined with middling.

// Example TBD