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.

Added functionality to remove the employee shift by using the unique shift id to both the server and client side.

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.