adblockplusandroid: Use Holo theme in Android 3.0 and above

This is an experimental change that allows us to use the modern Holo theme on Android 3.0 and above.

Here are some screenshots:

https://docs.google.com/open?id=0B0zm9ipEYmdqUlVzY2JCUWZfUEk
https://docs.google.com/open?id=0B0zm9ipEYmdqSHZtVlhzS1VTQVk

I had to set the build target to 11 for this to compile, so you'll have to get the Android 3.0 SDK. We can also use any later SDK.

I've tested it in simulators running Android 2.1, 2.3 and 4.1.

The changes are in the holo-theme branch.

[Felix Dahlke, 2013-01-02 08:28:42]

Closing this issue since Andrey carries on with this.