More refactoring of GUI tests.
* Input was switched from BufferedReader to Scanner so that tests could run. Simulated input was inputting two line breaks intead of one on every \n.
* Platform-dependent newline characters were used. This makes testing hard. Fix will be to remove all \n characters and replace them with System.out.println and to use System.lineSeparator() in test code.
More \n to LineSeparator fixes.
DeleteRecipe exercised to 100%.
100% BuyItem
AddRecipe 100%
100% addInventory
99.8% GUI!