Major changes to nsComboboxControlFrame:
Removed commented out code + nsIPluggableEventListener references.
Implemented nsComboboxControlFrame::GetNamesValues
Implemented nsComboboxControlFrame::SetProperty GetProperty methods
Fixed references to previously freed memory in nsComboboxControlFrame::ReResolveStyleContext
Modified ua.css style rules for dropdown-visible, drodown-hidden to have -moz- prefix.
Added -moz-dropdown-btn-out and -moz-dropdown-btn-pressed, -moz-dropdown-list rules.
Modified nsListControlFrame.cpp to calculate the width of the dropdown list for combo boxes correctly
Added nsListControlFrame::GetProperty and SetProperty methods.
Modified nsCSSFrameConstructor::ConstructSelectFrame to setup combobox.
2) Fixed ProgressMeter to update correctly when attributes change
3) Fixed sample8.html so that it does not over ride the borders of the HTML4 button this
messed up the active, hover, and disabled states.