Update to new pagination API

Fixes #36.

- Updated PaginationInfo JS -> Java
- Updated page indicator to include a range of pages when in multi-column
- Left/Right page buttons now enable/disable depending on canGoLeft/Right
Should we rename the canGoXX field names, so that they do not overwrite the canGoXX() method names in the PaginationInfo object?
In iOS launcher we append '_':
https://github.com/readium/SDKLauncher-iOS/blob/develop/Resources/host_app_feedback.js#L94