[mongoose] add unwind method with new params type

In mongodb 3.2, the unwind operator can with a object params.

mongoose/mongoose-tests.ts

@@ -1016,7 +1016,41 @@ aggregate.sort('field -test');
 aggregate.then(cb).catch(cb);
 aggregate.unwind("tags").unwind('tags');
 aggregate.unwind("a", "b", "c").unwind('tag1', 'tag2');
-
+aggregate.unwind(
+  {
+    path: "tags",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  })
+  .unwind({
+    path: "tags",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  });
+aggregate.unwind(
+  {
+    path: "a",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  }, {
+    path: "b",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  }, {
+    path: "c",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  })
+  .unwind({
+    path: "tag1",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  }, {
+    path: "tag2",
+    includeArrayIndex: "idx",
+    preserveNullAndEmptyArrays: true
+  });
+  
 /*
  * section schematype.js
  * http://mongoosejs.com/docs/api.html#schematype-js