Add wxQtProgressBar stub internal helper for gauge (just for generic events, no signal needed now)
Implement basic gauge methods (set/get range and value)
Implement wxSlider event handling (including internal wxQtSlider helper)
Implement basic slider methods (set/get range and value) in wxQT
Add text event and allow edition in wxQtComboBox
Implement spin button event (wxQtSpinBox internal helper)