Fix #15, Support multipart post.

examples/post-multi-part.js

@@ -0,0 +1,27 @@
+// Generated by ToffeeScript 1.6.2
+(function() {
+  var curl, p;
+
+  curl = require('../index');
+
+  p = console.log;
+
+  p('start');
+
+  curl('127.0.0.1/upload.php', {
+    multipart: [
+      {
+        name: 'file',
+        file: '/home/miao/test.js',
+        type: 'text/html'
+      }, {
+        name: 'sumbit',
+        value: 'send'
+      }
+    ]
+  }, function(e) {
+    console.log(e);
+    return console.log(curl.body);
+  });
+
+}).call(this);