Made program able to check multiple Twitter handles, new check system updates

-Added CommandLine code
-Added NormalGUI.java
--Normal GUI for PAXChecker
--Needs more work
-Made TicketCheck the manager for actual ticket checking
-Made CheckMethod the new TicketCheck
-Made TwitterReader instance-based
--Can set Twitter handle to check per instance
--Still uses the same API tokens
Fixed NullPointerException, updated ErrorWindow

-Made ErrorWindow variables private
-Made ErrorDisplay methods return the given ErrorWindow object
-Made CheckTwitter.java not throw NullPointerException
-Made PaxsiteReader return [null] instead of null value if unable to connect
Made CLI work, fixed bugs

-Made ShowclixReader.getSellerID() return 48 if expo is null
-Removed some extra unneeded output
-Made Check.run() final
-Made Checker.commandLineSettingsInput() use nextLine() for everything
--Can just hit ENTER to not input anything
-Made CLI ask for Expo before methods of checking for tickets
--Issue with CheckShowclix going off if expo wasn't Prime
-Changed version to 2.0.0 R4