This patch provides a set of formatters for most of the commonly used Cocoa classes.

The formatter for NSString is an improved version of the one previously shipped as an example, the others are new in design and implementation.
A more robust and OO-compliant Objective-C runtime wrapper is provided for runtime versions 1 and 2 on 32 and 64 bit.
The formatters are contained in a category named "AppKit", which is not enabled at startup.

llvm-svn: 151301