converts any object-oriented function's call to a functional call: o.f(args) => f(o, args)

• var O = {x: 1, y: 2, add: function(z){return this.x + this.y + z}}
• O.add(5); // 8
• var add = oo2fn(O.add)
• add(O, 5) // 8

• var toUpperCase = oo2fn(String.prototype.toUpperCase)
• toUpperCase('abc') //ABC