Added named colors from 4.3 Extended color keywords

::nana::colors::<named colors>

source/gui/widgets/widget.cpp

@@ -20,13 +20,16 @@ namespace nana
 	}
 	//class widget
 	//@brief:The definition of class widget
-		widget::~widget(){}
-
 		nana::string widget::caption() const
 		{
 			return this->_m_caption();
 		}
 
+		void widget::caption(std::string utf8)
+		{
+			_m_caption(std::wstring(::nana::charset(utf8, ::nana::unicode::utf8)));
+		}
+
 		void widget::caption(nana::string str)
 		{
 			_m_caption(std::move(str));