Kindle APNX: Add calculation using pagebreak tag.
fix equality.
fix indentation.
fix fiding pagebreak tags.
page apnx algorithm to search for all tags with pagebreak in them.
Put in some more fallbacks for when a chosen parser failes.
Kindle driver: When generating page numbers automatically, add an additional method to detect page boundaries, using the presence of <mbp:pagebreak> tags in the source of the book. You can use this setting by cright clicking on the Kindle icon in calibre when the kindle is connected and choosing customize this device. Fixes #1321761 [Code Submission: Real Page numbers modification](https://bugs.launchpad.net/calibre/+bug/1321761)

Merge branch 'master' of https://github.com/user-none/calibre