* Fixes issue #578
* -fadeOut was called by -willRotateToInterfaceOrientation, but -fadeIn was never called as it's part of didRotateFromInterfaceOrientation
Refactored references to PurchasesManager
Partial fix for #574

1. Open shelf
2. Read downloaded book
3. Select "Back to Baker Shelf"
4. Read the same book again
5. Select "Back to Baker Shelf"
6. Crash
Merge pull request #676 from waywalker/issue-578-no-index-view-after-modal

Fixes #578
Use shelf cover as a Newsstand icon
Better error management when retrieving shelf JSON
Fixed compilation errors in Standalone mode
Removed double IssuesManager initialisation
Better download management for shelf JSON

Closes #663.
Create JSON status files on init

This has the fortunate side effect of removing a lot of misleading "error when loading" messages from the log.
Merge branch 'master' into newsstand_notification