Import Shutterbug library
Use API 17 for Shutterbug
Modify ShutterbugDownloader to support on-device images
Add just-in-time image scaling to FetchableImageView
Add .gitignore for Shutterbug
Set up Executor for Shutterbug
If Shutterbug hits the heap limit, request GC and try again (up to 3x)
Use WeakReferences to ShutterbugManagerListeners so that their views can be GC'd
Remove unused/outdated FetchableOverlayItem from Shutterbug library
Make LruCache::trimToSize() public
Add low-memory callbacks to ImageCache
Use plain gray placeholder when loading images
Add remove() methods to the cache
Restore greyscale thumbnail mechanism
Refactor Shutterbug to use AndroidUtilities helper methods
Formatting and lint cleanups
Don't re-fetch a bitmap if the URL hasn't changed
Refactor caching to store rescaled bitmaps and avoid holding full-size bitmaps in memory when possible
Rename image cache to mention our app name
Hook up new scaling method. Should fix portrait stretching issues.