Support no-content (204) requests in BasicNetwork.

When we get an empty response for say, a 204, we create a 0 byte
response and pass it on to the NetworkResponse.  Implementers
of Request can then return appropriate Responses.  The behavior
before this change results in an NPE because we attempt to
getContentLength() bytes from a null entity..

Change-Id: Ia5f92ffd99b8f3e88cc92dc50ba43c4721d83e79
Signed-off-by: Ray Colline <rayc@google.com>
Merge "Support no-content (204) requests in BasicNetwork."
make all 2xx be a valid success codes

Change-Id: I94313e2f89c38277d36b7a2aaa525862d2740c98
Merge "make all 2xx be a valid success codes"
Fix default image not displaying prior to load

Previously, if a default image was set, it would not be displayed
until a network load had begun. In some use cases where the load
would not be started until some arbitrary time in the future, this
would leave an empty image view visible to the user. This patch
checks to see if there is a default image set, and if so, uses that
to clear the view, so prior to loading, the defualt image will be
shown.

Change-Id: I6fcee408d95d708676d68f3f0bc7222e56570f39
Merge "Fix default image not displaying prior to load"
Merge branch 'volley/master'