Default label, calendar, and tasklist

[keanulee]

Allow the user to set default label, calendar, and task list, which allows them to bypass the first menu for Mail, Calendar, and Tasks.

The first menu should still be created and pushed onto the window stack, and the user should be able to navigate back to the first menu by using the back button.

The user should be able to set the default label/calendar/tasklist by long-selecting that item in the first menu (with a "Set default <label/calendar/tasklist> to _?" confirmation window), or through Settings on the phone app.