revises config window
connects check boxes to variables
changes method names to 'on_' syntax
cleans up code a bit
reformats MainWindow construtor
adds functionality to the config window
makes config window functional for current configurable variables
adds a confirmation mechanism for deleting articles
fixes bug, where indicator wouldn't get into attention mode, when notifications were turned off
makes deletion mechanism respect the SHOW_DEL_DIALOG setting
expands the space between the treeview and the button layer