Replaced flying image for saved map vises

Title pretty much says it all!  Addresses issue #1604

I chose the image from open clip art.  The choices were (sadly) few and far between.  The new saved map vis thumbnail on the index page is shown below:

EDIT:  Removed the Flying Machine image.  Sorry about that!

![new_map_img](https://cloud.githubusercontent.com/assets/6451941/3635298/7d2dd1ac-0f69-11e4-8bdf-5cd6cb152f0b.png)