Added a remove all shifts by employee id method to the Schedule class. Now when an employee is removed there shifts are deleted first from the database then they're deleted after.

Changed update implementation for employees so rather than sending the whole list of employees when there are staff change, the server sends a message to all active clients to add/remove them locally. Also, changed all exception variable names to 'exception', and cleaned up warnings.

Fixed bugs with that caused in consistencies with message sending between client and server. All employee data should be updated to all clients when employee data is modified in the database. The client should have an updated copy of employee information.

Changed schedule and staff class so that the connection is made from the model and passed to the staff and schedule class.

Refactored Staff class to support local MySQL database. Now supports establishing connection to MySQL database, adding employees, removing employees, and printing all current employees.