Add support for being widowed

[6a74]

And since your modeling looks at someone marrying at age 30, you should also consider being widowed, since the surviving spouse will then have to start filing taxes as Single in the following year. The space in each tax bracket for Singles is half as much as for MFJ, but the spouse will still have to continue taking the full RMDs each year. Other incomes may also not be cut in half. I'd estimate the typical Boglehead survivor would have 65% of their married income. And I've seen age 75 be used here for the age of being widowed.

This is a great suggestion. I think I can add support for being widowed, it shouldn't be too difficult. If it happens before retirement, I will (by default) cut income to 65% of its current value. And I'll introduce a "become widow at" setting with a default value of 75. The "age of death" setting should be thought of as the death of both persons.