Did another pass at saving off the Turn state when backgrounding.

Attempted to fix issues due to incorrect code path happening on
first playthrough via massive rework. Preferences are now cleared
when exiting the Turn activity legally, and default values are
used to set the Turn up properly on a brand new OnCreate. This
required pausin the TurnSummary delay timer onPause.

Alternatively, we could clear the preferences every time we invoke
the TurnActivity, and remove the flag that ensures Turn is leaving
to next activity in OnPause().

Also fixed minor bug where you could pause during TimesUp! due to
buttons not being disabled.