Transforming Node-style APIs into Fantasy-Land Promises

usage"
```
var fs = require("fs");
var node = require("fantasy-promises/node");
var p = node.call(fs.readFile,'./myfile.js', 'UTF-8');
p.fork(
     function(d) {console.log(d)},
     function(err) {console.log(err)},
 );
```
Merge pull request #3 from pk11/master

Transforming Node-style APIs into Fantasy-Land Promises