Fixed a bug where the GUI ComboBox value would sometimes not match the
effect being displayed. This bug sometimes occurs when the GUI is first
initialized. This change now ensures that the ComboBox value is
correctly initialized.
Added a ComboBox to the GUI to allow the user to change the
visualization effect without having to restart Python. The user can now
select from one of the following visualizations using the GUI: 'Scroll
effect', 'Spectrum effect', 'Energy effect'
Fixed some bugs that occurred in Python 3.5 but were not present in
Python 2.7. Most compatiblity issues were caused by incompatible type
casting of numpy arrays.
