Improve animation performance

[bryanbraun]

One quick way for us to improve the performance of these animations is to rely more on transforms, as explained in this article (and the following image):

The biggest opportunities are in areas where we could animate transform: translate instead of top/bottom/left/right. We can fix this in the following screensavers:

• Flying Toasters
• Bouncing Ball
• Fish
• Logo
• Messages
• Messages 2
• Spotlight

Other opportunities include:

• Hard Rain (currently animates width and height).
• Rainstorm (animates background color, which could be done with opacity)