Recipes: do not trigger on a single ingredient alone.

With keyword 'recipe' we can always trigger, but require at least two
ingredients otherwise.

Fixes #1064.
Forecast: do not return reuslts for weather app/apps.

Fixes #865.
Merge pull request #1066 from mwmiller/forecast-relevancy

Forecast: do not return reuslts for weather app/apps.
Merge pull request #1065 from mwmiller/more_ingredients

Recipes: do not trigger on a single ingredient alone.