Remove generics from ImagePresenterCoordinator

No reason why it can't coordinate presenters for
different types of models
ImagePresenter comment/code cleanup
Update comments for ImageManagerLoaders
Remove misleading constructors from RecycleableBIS
Add comment for LoadedCallback
Call cb in background in VolleyStreamLoader

This means our code in the cb will run on a
background thread. Though all we do is post to a
thread pool, this change means we don't need to
acquire that lock on the main thread.
Comments for DrawableLoader
Increase Bitmap compression in flickr sample

Increases # of images that will fit into cache
Update a few comments and fix warnings
Fix more warnings and remove unused methods
Glide.load -> Glide.wrap.load

Clearer defaults with type safety and a little
closer to what actually occurs.
Add metadata to replace ImagePresenters if needed

This way we can do what users expect so if they
load a new model type or an old one with new
options we will actually load the new type
and/or with the new options.

This limits the api a little bit because we need
to be able to test equality, but all options are
still accessible by using ImagePresenter directly
and this was always intended to be an easy 
starting point.
Cleaner and more efficient Glide api

Reduces the # of extraneous object allocations by
lazily creating objects only if a new presenter is
needed. Adds some metadata to view tags to 
determine whether or not options for a view are
the same, so an existing presenter can be used
or have changed, so a new presenter has to be
created
Fix NPEs when cache directory already exists
Add defaults for loaders using Glide singleton
should have been a while ago