Updated notifications, error handling

-Made program wait for notifications to be closed before showing Setup
--Added CountdownLatch to NotificationHandler
-Made TicketChecker have private constructor
Enabled Twitter checking

-Made program able to check Twitter
--FEELS AND IS HACKED TOGETHER AT THE MOMENT
--Program requires Consumer, Consumer Secret, Application, Application Secret tokens
--Program currently only prints out PAX's latest Tweet
--Made Twitter API tokens encrypted in program memory
--Currently only finds the latest link from new tweet(s)
-Made TwitterReader more of a utility class
--No longer keeps track of latest Tweet
--Only gets Tweets it's told to
--Unfinished, needs refinement
-Enabled Twitter Checking in Setup
--Disables option if Twitter is not set up correctly
--Requires all four API tokens to work
--Added a "Why is this disabled?" JLabel if disabled
-Added command-line arguments:
--[-consumerkey KEY] -- Sets the Twitter API consumer key
--[-consumersecret KEY] -- Sets the Twitter API consumer secret key
--[-applicationkey KEY] -- Sets the Twitter API application key
--[-applicationsecret KEY] -- Sets the Twitter API application secret key
-Changed version to 2.0.0 R3