Added hover dropshadow to animal images

Added a simple dropshadow which appears when hovering over an animal's portratit
Added active sort button styling

Added the Active class to the currently active sorting button.

Added a minor dropshadow and hover effect when hovering over an animal's image
Added format_name, cleaned up format_breed

Added a format_name function, which chops off the animal's name if it is over 18 characters, and adds ".." to the end to indicate the name has been chopped.

Cleaned up format_breed to prevent a redudant if/else statement that was used to chop the breed string if it was over 22 characters long.