ButlerBot v2.0

ButlerBot version 2.0 complete.
Functionality remains similar to version 1.1, but with cleaner code and
increased functionalities, i.e. tagging.

ButlerBot v1.1

ButlerBot version 1.1 complete, switched from CLI to GUI.
Functionality remains as per version 1.0.

ButlerBot v1.0

ButlerBot version 1.0 complete, with ability to understand a fixed set
of commands (todo, deadline, event, mark, unmark, delete, list, bye).

Bot is able to store user input and load it up upon restarting the bot.

Full Changelog: https://github.com/jinyuan0425/ip/commits/v1.0