[FIX] Better VoiceOver support.
XIB for Xcode 4
[FIX] Verify GPGMail's bundle signature and abort to load if verification fails.

- Use SecStaticCodeCheckValidityWithErrors with kSecCSDefaultFlags flags,
  so that the verification makes sure that bundle contents have not changed,
  the main executable has not been tampered with and if other code within
  the bundle has also not been modified.
Better code sign check
Use PINENTRY_USER_DATA DESCRIPTION
Code signature check: NSAutoreleasePool added.
Some cleanup.
Allow setting a custom icon.
Better Keychain support.
[FIX] Don’t use imageForResource. [#122 state:fixed]
[FIX] Keychain support on Mac OS X 10.6.
CODE_SIGN_CHECK will be set outside from Xcode.
gpgStringWithCString added.
Prevent ultra long passphrases.
[NEW] ARC
Merge remote-tracking branch 'upstream/master'