Removed the annoying "Unable to connect" alert.

 - I think it's better to show the alert only when the action was
   initiated by the user.  Internet connection may come and go, but
   Reader Notifier disturbs the user with an alert even though he/she is
   not interacting with it.
Fixed feed proxy delegations
Change URL for preview to match current Google
Update to xcode 4
Merge remote-tracking branch 'alanshutko/master'

Conflicts:
	Reader Notifier.xcodeproj/project.pbxproj
Fixed feed quick add to use the correct API URL

As per:
https://sites.google.com/site/ursuleacv/knowledge/google-reader-api
Release 2.3, complete fork by netj

- Rewrote README (in Markdown).
- New place to distributed built versions. (file downloads are no longer
  supported at Github)
- Forked Sparkle appcast: new key, and URL pointing to my Dropbox.
- Wrote a small shell script for simplifying the process of creating zip
  archives, signing and deploying updates.
- Merged alanshutko's Google Reader URL fix.
- Growl framework 2.0.1.
  Notification Center support comes for free on OS X 10.8!
- Sparkle Korean language support.