Cache update should be done after database writing and not before, if we want to take profit of the cache.
Use cache to find out if we should write a new "flagged"/starred status into database.

Should speed up Google Reader refreshes.
Fix opening articles pages (sequel of issue #117)
Hack our formatters to handle timezone indicators containing a colon, like +08:00 and -05:00

Should fix <http://forums.cocoaforge.com/viewtopic.php?t=25749&p=135854#p135854> 
Anyway, [XMLParser +parseXMLDate] is relatively flexible with not overly exotic cases.
On Snow Leopard, ArticleListView's cells looked too tiny.
Improve on the previous commit : this seems more eye pleasing, from my point of view.
Could not select Google Reader feeds when creating/editing a smart folder.
Merge pull request #127 from barijaona/database

Database
Merge pull request #128 from barijaona/bugfixes

Fix opening articles pages (sequel of issue #117)