Add functionality for computing family benefits

[Gregable]

From a user:

One add that might be helpful would be to incorporate family benefits (e.g. when one spouse is >62 and has minor children living at home).

[Gregable]

Another request for this:

Is there any way you can enter a children input section? Some folks have children that may be able to receive benefits as well - until they turn 18. That could really help folks get a better idea of what they may be tossing in $ by not claiming SS @62. It helps folks determine the break-even point, often 76-80 years old, which with that addition many could find its in reality 82-85 prior to break-even.