V_Sim specific widgets

DumpDialog - Defines a widget to export into different file formats.
NumericalEntry - Defines a widget to enter numerical values without any boundary or precision constrains.
OrientationChooser - Defines a dialog widget to choose the camera position.
ToolPanel - Defines a widget that hold a set of V_Sim panel.
ColorComboBox - Defines a specialised GtkComboBox to choose stored colours.
ShadeComboBox - Defines a specialised GtkComboBox to choose pre-built shades.
StippleComboBox - Defines a specialised GtkComboBox to choose patterns for lines.
LineObject - Defines a specialised GtkHBox to choose all characteristic of lines.