Match .carousel-inner specificity to beat styles

'.carousel ing' was replaced with '.carousel-inner > .item > img' in
3.0 and now loses the specificity war. To make carousel images 500px
tall, match specificity to make carousel.css win.
Update carousel example JS path

'bootstrap.min.js' lives in '../bootstrap/js' now. Switch to the
minified version for a smaller download since this example is focused
on CSS changes, not JavaScript ones.