fixed carousel js

Updated slick stylesheet link, jquery call, slick script to CDN.  Fixed javascript code of slick carousel in main.html.
js code error

fixed minor js code error
final carousel fixes

inserted zoo-appropriate images, refined slideshow to eliminate arrows, run smoothly.
carousel images fit

set carousel images to fill carousel width.
Merge pull request #3 from CodeLouisville/Rick-fixing-slick-carousel

Rick fixing slick carousel