Previous/next page buttons not always disabled when reaching start/end of EPUB

[danielweck]

(reported by Bogdan)

This problem may be due to two-page synthetic spread display only, as it seems to work in single page mode.

eBook:
https://code.google.com/p/epub-samples/downloads/detail?name=page-blanche-bitmaps-in-spine-20120809.epub

Note that SDKLauncher-OSX handles this fine.

Screenshot:
https://www.dropbox.com/s/d3pnwpji7b7s282/last_page_bug.png

[danielweck]

Thank you @grigaci (Bogdan Iusco) for looking into this, and for your proposed solution. Before we embark upon implementing a RDServices-based solution (shared between iOS and OSX launcher apps), I would like to try to fix this problem at the shared-js level, so that we can address the js-viewer shortcomings too:
readium/readium-js-viewer#117
readium/readium-shared-js#79

[danielweck]

Fixed by Pull Request #33