Remove broken links from hello world example

examples/helloworld/README.md

@@ -1,17 +1,10 @@
 ## "Hello World" overview
 
-This example is a minimalistic application of the pdf.js project. The file
-`helloworld.pdf` is from the GNUpdf project (see [Introduction to PDF at
-GNUpdf] (http://gnupdf.org/Introduction_to_PDF)), and contains a simple and
+This example is a minimalistic application of the PDF.js project. The file
+`helloworld.pdf` originates from the GNUpdf project and contains a simple and
 human-readable PDF.
 
-
 ## Getting started
 
 Point your browser to `index.html`. Voila. Take a peek at `hello.js` to see
 how to make basic calls to `pdf.js`.
-
-
-## Additional resources
-
-+ [GNUpdf - Introduction to PDF](http://gnupdf.org/Introduction_to_PDF)