Can't parse Pages 5.5 format (probably any Yosemite-iWork files)

[stephenlind]

Apple updated the format again, so it's broken on Yosemite's version of iWork.

It seems that the change Apple made is trivial -- rather than using an index.zip inside their top level bundle, they've simply made the .pages file a zip. I'll follow up with a pull request, you can decide if this is an appropriate solution ;)