Fixing issues #8-11

@vokalinteractive/ios-developers Code review? Only about 10% of this is code that I typed, the rest occurred because of Kif in a pod update.
I would strongly recommend against using categories on `NSString` for this, in large part because of the potential for namespace collisions.  I'd prefer a class like `VOKMultiImageLocalizedString` with just class methods that all return `NSString` objects.