Closing #98. Animated GIFs were losing their transparency and animated properties when saved as avatars. Reworked the avatar save process to only run the avatar through PIL if it is too big. This preserves the original uploaded file if it is within the desired size settings. This may still mangle big animated gifs. If this becomes a problem, then maybe look into calling the PIL Image.resize() method directly. Moved the PIL image specific functions from bio.forms to a new module: core.image for better reusability in the future.