Added a Today fragment, refactored TodoPanelFragment

I found out you cant nest fragments in fragments in static layouts prior
to Android 4.2.  So, refactored fragments into TodoPanelFragment and
TodayFragment.  The smaller parts (TodoListFragment, SortBarFragment,
NewTodoFragment) are all unused at this point.  The TodoPanelFragment
and TodayFragment have 'redundant' sort bars and todo lists, so I may
need to share code some other way than fragments.  Perhaps only for the
sort bar, because the todo list in the TodayFragment is fundementally
different than TodoPanelFragment, since is is a mix of tasks from other
lists.
Added code to create lists and create tasks.

This code is rudimentary.  It does not yet persist the data.  There is
no detail for the task, just a name.