Some battery stats history fixes.

- Now the full wake history uses the history tag if it can.
  Hopefully this will still result in a consistent history,
  since that isn't really want the tag is for...  but the
  current implementation in places will probably make this work.

- Possibly fix a bug with inconsistent state between partial
  history snapshots: after a snapshot is printed, don't allow
  any more batching into the most recent history entry, so the
  next snapshot will not miss anything that might get placed
  into it soon after.

Also rework command line arguments for enable/disable to make these
commands instead of options.

Change-Id: Ia33445cad1538bf8df549cef284f1e736efbc079