Bringing code up to date with Field Guide Functionality and iOS 6

Added code changes that mirror the field guide changes
- Fixed issues with iPad opening in landscape
- "Menu Button" now displays label in both landscape and portrait mode
- Full screen in iPad landscape mode
- Fixed issue with iPhone/iPod Landscape images
- Added default screen for iPhone 5
- Added image and audio ordering
Fixed thumbnail references for simulator

Filenames in the simulator are case-sensitive.
Put database build into background context

Changed the database building code to use a different context to the
main code, based on Ryan Maxwell's commit to the Field Guide Code.