Categories, recipes and ingredients now saved in hashmap together with their associated code and a whole bunch of refactoring to go along with it. TypeAdapters for Recipes, NutritionTables and Categories. Saving and retrieving Recipe, NutritionTable and Category to / from JSON works (see tests).

Added parser to retrieve Ingredients from CSV files. includes tests. toString method for Ingredients. new NutritionTable constructor to create objects from List<Double>.