Fix race where placeholder might not be set.
Add debugging bitmap tracker.
Fix concurrency exceptions in GifResourceDecoder.
Abort disk cache edits if throws while writing.
Add lifecycle + listeners
Fix application RequestManager initialization.
Handle context wrappers in RequestManagerRetriever
Use LifecycleListener to stop/start gif animation.
Explicitly start/stop GifDrawables.
Fold GifData into GifDrawable.
Add GlideBitmapDrawable.
Make GifDrawable implement GlideDrawable.
Use explicit GlideDrawable class.