Gratin 0.4.0: themes, timers that keep going, and a round of beta fixes

Most of this release came from our first beta tester's feedback. Thank you. New Themes: Light, Dark, Black and Paper. Choose one in Settings. Timers that keep going after you close the app: a timer tray, a banner when a timer rings, timers on their own step, and a system alert when one finishes. Hide a generated magazine, or keep it as your own. Show ingredients in the order they're used in cook mode and magazines, without changing the recipe. Fixed Timers keep time in the background, and can be cancelled. Ingredient headings stay headings in cook mode. Switching an ingredient line to a section no longer crashes. Reordering ingredients no longer rewrites the recipe. The bottom bar and keyboard no longer cover a recipe on phones. Groceries no longer merge different items that share a word. Generated magazines no longer put recipes in the wrong cuisine. Filter tag suggestions come from the recipe book you have open. Web imports no longer save the site's rating as yours. Meal plan dates no longer land a day early east of UTC. Advanced sync opens below its switch. Screen text no longer gets selected by accident. See what's coming next on the roadmap.