Resolve IllegalStateException, Fragment not attached to Activity.

It appears that isDetached() != isAdded(), and isAdded() is the correct
check to use.
Handle BitmapFactory.decodeFileDescriptor throwing an IOException.

This can happen (although is not documented as such) in
BitmapFactory.nativeDecodeFileDescriptor.  Throw the exception up in
ImageResizer.decodeSampledBitmapFromDescriptor, and catch and ignore it
in ImageFetcher.processBitmap.

Update the documentation and add @Nullable annotations to make it
clearer to future readers of the code that this is OK.
Add an isAdded() check in updateUIForPlayer.
Merge remote-tracking branch 'kaaholst/master' into develop
Check items.size() to avoid NPE, not whether items.get(0) != null.

The previous code didn't actually avoid the NPE.
Prepare for release 1.0.1.
Merge branch 'release-1.0.1'