Feature Request: Indented List with Subtotals

[jpfieber]

If I wanted to track everything during the day, I can add it all to one list, but sometimes it's nice to see the breakdown by meal. I could create a separate 'diary' for each meal, but then I don't see the total for the day. What if you could subtotal the products by meal, and then have the grand total at the bottom? For example:

```fooddiary
[Breakfast]
Cereal 250
Eggs 300
[Lunch]
Tuna Sandwich 350
[Dinner]
Steak 500
Potatoes 450
```

Would produce something like:

| Meal | Product | Calories | Protein | Fat | Carbs |
Breakfast               250          30         25      17
             Cereal       150          15         10      15
             Eggs          100          15         15      2
Lunch                    320           19         12      12
             TunaSa     320           19          12      12
Dinner                   800           30           20     10
             Steak         500           25         15       5
             Potatoes    300           5           5         5
TOTAL                    1370         79          57       39

I'm not saying this is the best way to format things, but it's an idea of how you could call out 'meals' and every product under a meal could be considered a part of that meal until the next meal was defined. People could then call the 'meals' whatever they want, and could have as many as they need throughout the day.