WIP: loader resolvers.

Change-Id: I44d7abdc166c4f3affbe469e3d8281e1e388c25e
Move deepZoom into BitmapFetcher.
Enable fastLoad support for deepZoom.
Use BitmapFactory to load non-animated gifs.
Fix up ImageView cached exception delivery.
Clean up execute/request resolution to properly invoke onto main handler.
Use BitmapFactory.decode with bounds to get the image mime type instead of isGif.
Replace IonBitmapCache.decode(InputStream, ...) variant with File.

Change-Id: I724e02d06392fba367e05776773761edb4ff8a44