Fix some things in settings: manage apps, battery, procstats

Issue #17461567: java.lang.ArithmeticException: divide by zero when
looking at Settings > Battery

Yeah, let's not do that.

Issue #17365562: Running services RAM totals are wrong

Okay so like a few months ago, I had this vacation coming up, and
it was around the feature complete (hahah) deadline, and I had to
rush to get this in before I left.  So I rushed.  And, well, I forgot
a few things.  Here they are.  We now show the right numbers and
even update things correctly when you change what processes are
being shown.  Wow.

Finally, fixed a few issues in the dev tools procstats UI.

Change-Id: I8348a9c2ec3226a455c5c8465729e4487f324c8b

src/com/android/settings/fuelgauge/BatteryHistoryChart.java

@@ -1011,7 +1011,7 @@ public class BatteryHistoryChart extends View {
             mTimeRemainPath.close();
         }
 
-        if (mStartWallTime > 0) {
+        if (mStartWallTime > 0 && mEndWallTime > mStartWallTime) {
             // Create the time labels at the bottom.
             boolean is24hr = is24Hour();
             Calendar calStart = Calendar.getInstance();