extend PreferenceActivity for title text on a single pane mode

startPreferencePanel() ignores titleText on a single pane mode
this commits extends PreferenceActivity by adding EXTRA_SHOW_FRAGMENT_TITLE_TEXT to intent

ported from CM9, http://review.cyanogenmod.org/#/c/14919
AOSP part verified, but not merged

Change-Id: Ie0702dc20b17504148f4da9cc83a6d7865d95423
Allow purging of asset bitmaps

It seems that neither CM9 nor CM10.x includes the actual framework-side
code to facilitate user-controllable bitmap purging. Odd, since the
CyanogenMod Settings app in both CM9/CM10.x includes the option.

Backported from original Gingerbread commit:
http://review.cyanogenmod.org/#/c/3908

Original description:

Allow the system to reclaim more free RAM when needed on 'low' memory devices
(e.g. Droid/Milestone) that are struggling with 2.3. This option enabled
efectively restores the froyo way of forcePurgeable BitmapFactory asset
handling.

Change-Id: I6a3b8a05b7be9c214a8548d6c6d1621e6533a1e0
Monitor device storage directly in /data/data

The DeviceStorageMonitorService watches over /data, and when things get
full, starts deleting app cached files.  The app caches are actually
under /data/data, which on DINC is its own mount.  This means the
monitor did not notice when app cache grew too big, as it only saw the
size of /data proper.

This patch makes the monitor look at /data/data instead.  For DINC, this
means it can properly manage app cache, but it won't notice if the upper
/data partition is getting full.  That's not as common as /data/data
filling up though.  For the Samsung devices that mount a /datadata and
then symlink to /data/data, it should also work, as statfs dereferences
links first.  For all other devices with only /data, reading statfs on
/data/data still yields the total/free sizes of the /data partition.

Change-Id: I118a85a04c3a257d54d40ce7802426b4e0fe3e87

Conflicts:
	services/java/com/android/server/DeviceStorageMonitorService.java