pkp: po alternative to lookup via valueForKeyPath:

pkp is a command to print out a key path.   LLDB has pretty bad . notation resolution, especially through (id) return results, so I've been using [self valueForKeyPath:@"whatever.keypath.failed.inlldb"] to work around this.   This helper makes that very easy!


![screen shot 2014-11-20 at 4 23 12 pm](https://cloud.githubusercontent.com/assets/114322/5133252/a0690ece-70d1-11e4-86b4-3a9549e818a0.png)




So I added some basic stepping through the key path, but an object can return a value from `-valueForKey:` and return false from `-respondsToSelector:`.    So I'm not sure this will work without some more thought.  There's no `-respondsToKey:` functionality.

I'm not sure if you use FuzzyAutocomplete, but that does perform a good deal of completion/typo fixes when using po (when it works).   pkp does not get the auto-completion help like po does though.   Any idea how that could be fixed?