Merge pull request #670 from waywalker/landscape-only-issue-not-rotated-at-opening

Fixes issue #642.
Refactored methods to retrieve prices
Disabled alerts on App Store connection failure

Alerts won't pop up anymore when retrieving prices while there's no connection to the App Store.
Alerts will pop up as usual when the price retrieval is initiated by a user interaction.
Fixed Value Conversion Issue warning
Fixes issue #705 (part 1 -- no Index View after mailto)

- moved addObserver to -viewDidLoad to prevent duplicates when -viewWillAppear is fired multiple times
- added removeObserver to dealloc for cleanliness
Fixes issue #705 (part 2 -- restore Scroll Index after mailto)
Merged 'upstream/master' and resolved a conflict with b0fb595