Tack on a (nil) argument if the selector is asking for one
don't set identifiers on pasteboard objects

fixes #1597
Merge pull request #1730 from quicksilver/i1597

don't set identifiers on pasteboard objects
never try to get a result from performSelector. The docs say not to

The use of result was never actually implemented anyway, and was causing a crash
Merge pull request #1724 from quicksilver/sendMessage

Tack on a (nil) argument if the selector is asking for one