Allow any Blob to be uploaded

`File` is a subclass of `Blob` and thus this will still accept any `File` as before.

The benefit of also allowing `Blob` is that those are user-creatable, and you can get them from a `Canvas` if you are e.g. resizing images in the browser before uploading them.

Author: LinusU

src/ParseFile.js

@@ -109,7 +109,7 @@ class ParseFile {
           base64: this._data,
           type: specifiedType
         };
-      } else if (typeof File !== 'undefined' && data instanceof File) {
+      } else if (typeof Blob !== 'undefined' && data instanceof Blob) {
         this._source = {
           format: 'file',
           file: data,