Fix a leak
Fix a static analyzer error
Some changes suggested by Xcode 5
Improved safeguard of the list of open tabs

Bug described at http://forums.cocoaforge.com/viewtopic.php?t=26391&p=137525
Tabs should be opened before being saved.
Handle situations where OpenReader server is down

"Refresh all subscriptions" is now able to refresh at least the local feeds when the OpenReader server is down.
Improved UnifiedDisplayView
Subtler indicator for OpenReader feeds