[Patch][ObjC][Proposal] NSValue literals

Patch extends boxing expressions to support NSValue.

Some C structures might be boxed into a NSValue, e.g.: NSPoint, CGPoint, NSRect, etc.
This patch extends boxing expressions to accept the structures, that could be used to construct NSValue object:

NSPoint p;
NSValue *point = @(p);
CGRect r;
NSValue rect = @(r);

Full list of supported structures:
NSPoint, NSSize, NSRect, CGPoint, CGSize, CGRect, NSRange.

nsvalue_literals.diff (19.1 KB)

Just realized that I sent it to a wrong list.
Will resubmit to cfe-commits.
Take my apologies for the mess.