Created Message Abstraction

MessageItem represents various messages found in the log
Added message parsing

Added new method to parse message to classify and allow for operations on messages
Parses user id for login and logout events

Parsing finds usernames for LOGGED_IN and LOGGED_OUT events.

Fixed semantic error initializing LogItem
Added Testing for MinecraftLog

Added unit tests to prevent regressions for further feature additions
Created test case for log events to ensure constants are applied correctly
Added test case for users when applicable

Some event have users. When an event is reconized and parsed the user data is extracted and attributed to the MessageItem