Retain order of ingredients

The current load of ingredients is by the node ingredient record id, essentially meaning it is a time-based order. When updating ingredients, this can cause some confusion. During edit, some updates of ingredients will suddenly fall to the bottom of the list with no obvious reason.

This patch adds a "weight" column to the recipe_node_ingredient table. It also alters the recipe_ingredients_diff and save function to use the order of the ingredients as the weight. Down the road this would open up the door for "move up" and "move down" controls similar to views. For now this at least keeps things in the same order you entered them at the node level.

I took an initial pass at writing the upgrade for this database change, and altering hook_install for both database platforms. Needs testing and review.