Updates to Dianne's Dungeon.

 - new EKG icon
 - set the notification timestamp to the oldest service
   start time, so you have some idea how long things have been
   this way
 - minor text fixes

Bug: 36891897
Test: runtest -x cts/tests/app/src/android/app/cts/ServiceTest.java
Change-Id: I37c76ae86bcaee7c946863add041bbd1ca678cf9