Four weeks later and the pdf.js viewer is now functionally complete.
Based on the earlier discussion between myself and Peter it remains
disabled in Chrome on Windows, but I've had a generally good
experience on all the other platforms that I've tested on, including
Safari on iOS.
The last part is the update of the README file, which I will aim to do
this week so we can get a 2.x release out.
If anyone else has found issues with the functionality or the general
compatibility then please report those in the Issues section ASAP so I
can review them.