This patch updates the `IPDFStreamReader` interface and ensures that the interface/implementation of `network.js`, `fetch_stream.js`, `node_stream.js`, and `transport_stream.js` all match properly.
The unit-tests are also adjusted, to more closely replicate the actual behaviour of the various actual `IPDFStreamReader` implementations.
Finally, this patch adjusts the use of the Content-Disposition filename when setting the title in the viewer, and adds `PDFDocumentProperties` support as well.
It seems that the status check, for non-HTTP loads, causes the default viewer to *refuse* to open local PDF files.
***STR:***
1. Make sure that fetch support is enabled in the browser. In Firefox Nightly, set `dom.streams.enabled = true` and `javascript.options.streams = true` in `about:config`.
2. Open https://mozilla.github.io/pdf.js/web/viewer.html.
3. Click on the "Open file" button, and open a new PDF file.
***ER:***
A new PDF file should open in the viewer.
***AR:***
The PDF file fails to open, with an error message of the following format:
`Message: Unexpected server response (200) while retrieving PDF "blob:https://mozilla.github.io/a4fc455f-bc05-45b5-b6aa-2ecff3cb45ce".`
