Add image preloader

add jquery.imgpreload.js to app and bower/grunt config
Set up app base markup and CSS
Replace locally hosted SoundCloud JS SDK

Replace locally hosted SoundCloud JS SDK with SoundCloud-hosted version.
Implement and test SoundCloud auth
Set up main visual frontend and nav elements
Create callback page for SoundCloud auth
Set up imgur API connectivity & image loading

- Connect to imgur to obtain meme subgallery images
- Add preloader JS for imgur images
Update README.md with intro and APIs used