Added recursive hotkey search feature

Hey guys,

I've added a feature which allows you to do navigate through the option by repeatedly tapping the same character, so that it behaves exactly like a plain select element. For example, if you have a list of all countries in the world, tapping "a" four times will get you to "American Samoa", tapping "i" three times will get you to "Indonesia". This of course, will respect the type-as-you-go search, meaning, typing "ice" will still get you to "Iceland".

You can try the demo with the countries list here: http://jsfiddle.net/6784L/1/

I've left several comments on how it works on the code, so you can see how it works. 

I think this will make DropKick more accessible and behave exactly the same like a plain select element. What do you guys think of this? Cheers :)