Added test files for convenience
Removed dependence on QtButtons for showing plots

The show_plots now takes in a list of names to display the plots instead
of buttons. This allows for more flexibility and more modularization
Separated graphing from the main program

The central graphing widget was moved to a separate class to allow the
main window to be used in different projects in the future. The creation
of the graph and the buttons is now under the control of the graphing
widget class