Added 2 small features: Docking to an element and autohiding the indicators

First of all, big thanks for this component, saved me a ton of time and was almost exactly what I was looking for.

For my needs, the carousel needed to be inside a container with a hidden overflow, therefore the indicators were getting lost as they are at the bottom and just adding a padding would not work as the inner size of the container was not fixed. So I added an optional attribute that allows you to specify an element to dock the indicator to.

Also added the option to autohide the indicators; that is to show them only if there are only 2 or more slides in the carousel.

I think the changes are pretty unobtrusive (sorry changing the background color by 0.2 :) )

It is all documented in the readme and the code if quite straightforward and documented. You can see how it all works here: http://doukasd.com/

Cheers,
Dimitris