Fix CanvasView
Fix CompView
Fix bug in CanvasView
Fix DeviceTracker
Fix DialogSettings
Fix IconController
Fix gui::Instance
Fix MainWindow
Fix Preview
Fix WorkArea
Fix Renderer_Background
Fix build options (gui/Makefile.am)
Remove ruler includes
Fix bugs in Cellrenderer_Timetrack
Fix typos and simple compilation errors
Cairo rendering for Widget_Color
Cairo rendering for Widget_ColorEdit
Cairo rendering for Widget_Curves
Cairo rendering for Widget_Gradient
Cairo rendering for Widget_Defaults