make all 2xx be a valid success codes

Change-Id: I94313e2f89c38277d36b7a2aaa525862d2740c98
Merge "make all 2xx be a valid success codes"
Merge branch 'master' of https://android.googlesource.com/platform/frameworks/volley
Custom modifications to the library :

- Allow target dimensions to be set in NetworkImageView
- Don't treat non 5xx responses as errors.
Allow Bitmap.Config to be specified in ImageLoader#get /
NetworkImageView#setImageUrl
Remove from Disk cache on OutOfMemory
Prevent NPE in Request
Addded annotations to make lint happy
Check nullness before closing