Modified removeClassButton method by adding printing option before class's deletion.
Saving SimulationManager.java, LoginGUI.java and .form so they are not overwritten.
Change in MaintenanceManagerGUI: Able to double-click student in JTable in class control tab and have them appear in student control tab.
Changed a line in the changeUserNameButton.
Eliminated some errors in MaintenanceManagerGUI.java
MaintenanceManagerGUI: Updated changeUserNameButton method an changeRealUserNameButton method.
Merge pull request #25 from KettyLezama/master

Changes in MaintenanceManagerGUI.java: removeStudentButton method