Meal planner: page flickers when meals are added / moved

[jayaddison]

Describe the bug
In the meal planner, adding or moving recipes in the weekly calendar causes the contents of the planner to momentarily flicker.

To Reproduce
Steps to reproduce the behavior:

1. Perform a recipe search and add a recipe to a meal plan
2. Navigate to the meal planner view
3. Drag the added recipe onto an upcoming day of the week
4. Observe content flickering when the recipe is dropped into the day row
5. Move the existing recipe -- or equivalently, drag another copy of a recipe -- onto an upcoming day of the week
6. Observe that the existing and new content both flicker when the recipe is dropped into the day row

Expected behavior
Content should maintain visibility while dragging and when dropped into a meal planner day row. Moving or otherwise adjusting items in the meal planner should not cause any flickering of any existing or newly-added items.

[jayaddison]

This happens because we re-display the list of meals whenever the contents of the db.meals table is modified.

That's a simple and lazy approach, and the key benefit is that it makes maintaining the consistency of the database table and the view easy. The flicker occurs when the view elements are emptied during the refresh.