Recipe scaling

[barneyb]

Several related changes:

1. Remove nulls before diffing for recipe history. This was the source of the "can't delete subrecipe" over break.
2. Better handling of spaces and commas when recognizing "complicated" raw values. I've made the same changes client-side, but haven't pushed them up yet.
3. Bring auto-recognition (which happens sending to plan) inline with how the client does it. In particular, parse a quantity even if there is no ingredient.
4. Don't treat the lack of a quantity to mean "one count".
5. The big one: don't scale subrecipes onto the plan, or when computing recipe history after cooking it.
6. The bulky one: consolidating has/noValue checks. All mechanical.