Adds a ListEditEmojiDictionaryField (inherited from Michelle Aubin's 

ListEditDictionaryField class), which takes in a dictionary of values and

splits it into a tuple of (key, value1, value2, value3).
EmojiFileInput class is a subclass of FileInput, which takes in a file 

upload from the user, and saves it into the context variable. In future

implementations, the get_context() method can also be used to render image 

previews if the file uploaded is a valid image file.

Unit testing: Unit test suites for ListEditDictionaryField and ListEditField

Local testing: making sure the app runs property with print() statements.