initialize the colour to be invalid if the name passed to the ctor is invalid (bug 1891235)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@51769 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/colour.h

@@ -24,9 +24,13 @@ public:
     // constructors
     // ------------
 
-    // default
     wxColour() { Init(); }
-    DEFINE_STD_WXCOLOUR_CONSTRUCTORS
+    wxColour( ChannelType red, ChannelType green, ChannelType blue,
+              ChannelType alpha = wxALPHA_OPAQUE )
+        { Set(red, green, blue, alpha); }
+    wxColour( unsigned long colRGB ) { Set(colRGB); }
+    wxColour(const wxString& colourName) { Init(); Set(colourName); }
+    wxColour(const wxChar *colourName) { Init(); Set(colourName); }
 
 
     // dtor