Port CacheHeader away from ObjectOutputStream.

The standard Java serialization system relies heavily on
reflection, even for primitive types and Strings, which
generates a lot of garbage. Move to a simple built-in
implementation.

from original volley repo
Allow per-app VolleyLog tags

To clean up the logs when multiple apps are using Volley, optionally
customize the VolleyLog tag so that the app has its own namespace.

from original volley repo
NetworkImage - fix nullPointerException.

1. getLayoutParams() can be null.
2. old version used LinearLayout.LayoutParams instead of ViewGroup.LayoutParams

from original volley repo
Remote executable bit from ImageLoader

This shouldn't have been executable.

from original volley repo
Merge branch 'master' into develop
Merge branch 'release/2013-08-02'