Turn -implicit-objc-with on by default <rdar://problem/16795899>.

Swift SVN r17796

include/swift/Basic/LangOptions.h

@@ -62,7 +62,7 @@ namespace swift {
     /// Whether to make the "with" at the beginning of the first argument of
     /// an initializer implicit (i.e., dropped on import, added when computing
     /// a selector).
-    bool ImplicitObjCWith = false;
+    bool ImplicitObjCWith = true;
 
     /// Enables checking that uses of @objc require importing
     /// the ObjectiveC module.