Squashed all Superuser related commits

Squashed commit of the following:

commit e78a8556c602a290b26c72a76ef70f8d5b48ac76
Author: Koushik Dutta <koushd@gmail.com>
Date:   Sat Mar 30 16:24:58 2013 -0700

    SECURITY FIX: Fix package uids being reused between uninstall and reinstall of different packages.
    Policies for older packages were being granted to the newly installed package that got the recyled uid.

    Change-Id: I6c74cf6762e8da10e09d5cf5d94e9f826e47f24d

commit 76b5193a78d9e7adb3fdb7fa9615c0b75ab3ca9a
Author: Danny Baumann <dannybaumann@web.de>
Date:   Mon Mar 11 10:35:01 2013 +0100

    Fix scrollbars appearing out of place in Superuser.

    Change-Id: Ia206623716192e479901c02cf94de84a29e0479e

commit f475d9e7a9a1adf0341c476c763e07fb5c06e2bb
Author: Koushik Dutta <koushd@gmail.com>
Date:   Thu Feb 28 14:49:24 2013 -0800

    Switch to new Superuser

    Change-Id: I9d91392ad6fbc9953d19059ab59b91d214c00e0c

    Conflicts:
    	Android.mk
    	proguard.flags