Polymer 1.x and new features

Converted to Polymer version 1.x.x

New features:

• More Chromecast photos
• Popular and fresh photos from 500^px
• Interesting photos from Flickr
• A scheduler to control when the screensaver, display, and computer should remain on
• Optionally show on all connected displays
• Optionally display current time
• Additional photo sizing and animation options