Fixed crash when selecting document that is not available locally.

E.g. App Store review guidelines
First attempt at iCloud sync for bookmarks (based on UIDocument)
Sharper app icon on retina devices
Working on a reimplementation of the bookmarks manager...

This isn't finished yet, but the basic idea is to abandon UIDocument in favor
of writing the bookmarks file directly (coordinated of course). This has the
benefit of faster sync (because we don't have to wait for the document to auto-
save) and (hopefully) a cleaner method of dealing with the bookmarks file 
disappearing from iCloud (when the user deleted it from the system preferences).
Use new bookmarks manager in the UI.
Fixed an issue that could cause bookmarks to stay when the iCloud file was removed.
Removed old bookmark manager and some cleanup
Bumped version number to 1.1.
Retina launch images and higher resolution for background texture
Some refactoring in BookmarksManager
"Show Bookmarks" button on iPhone without having to open a document first
Added iCloud sync log UI and status button
Moved iCloud status button on iPad
Move a bookmark to the top if it already exists, instead of creating duplicates
Removed .docsetsbm document type from Info.plist
Support for landscape orientation on iPhone
Support for zooming on iPhone and reduced header font sizes
Fixed a bug with loading local bookmarks (iCloud off or simulator)
Removed failureReason from sync log (apparently always nil)
Removed old bookmark code in DocSet class