Improve process tracking.

We now keep track of when each process is running, batched
by the current memory status of the device.  In addition,
the stats are organized by package first, and then processes
associated with each package inside of that.  Finally, we
also keep track of the overall time spent in each memory
status.

This should start to actually get us to some information
we can reach some conclusions about.  The total time spent
in each memory status gives us some indication of how much
we are running while memory is low; the new package organization
batched by memory status lets us see what packages have
what processes running when memory is low.

Change-Id: I389d62d39d115a846126cf354e4c20070d8f1180