ENH: Adding Error Feedback to Qt GUI
- Added the ability to fetch the alert pixmap from the UI Manager so we can centralize it's access (and have the ability to change it easlily in the future)
- Added alert icon to qtGroupView - this is needed since the view needs to have a scaled version
- added modified signal to qtBaseView to indicate if the view was changed
- added isValid method to qtBaseView to indicate if teh view is valid
- added a signal to qtAssociationWidget to indicate if the widget's availablility infomation has changed
Closes #347 (closed)