Created on Jan 7, 2010
@author: tw55413
Generic progress page for a wizard.
Subclass and reimplement the run method. And within this run method, regulary emit the update_progress_signal and the update_maximum_signal.
the update_maximum_signal should have as its single argument an integer value indicating the maximum of the progress bar.
the update_progress_signal should two arguments, the first is an integer indicating the current position of the progress bar, and the second is a string telling the user what is going on.
If required, set the title and sub_title class attribute to change the text displayed to the user.