adds attributes 'quantity' 'unit' and 'short_name' to Entry class

[kittenwhisky]

split out 'quantity' and 'measuring unit' from entry name

example: if entry.name is 'Alpro - Soy Milk: Unsweetened, 100 ml' returns the following:

entry.quantity = '100' entry.unit = 'ml' entry.short_name = 'Alpro - Soy Milk: Unsweetened'