Implement wxColour constructors to match other ports by adding char const * and wchar_t const * constructors.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@47174 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/cocoa/colour.h

@@ -36,6 +36,8 @@ public:
         { Init(); Set(red, green, blue, alpha); }
     wxColour(unsigned long colRGB) { Init(); Set(colRGB); }
     wxColour(const wxString& colourName) { Init(); Set(colourName); }
+    wxColour(const char *colourName) { Init(); Set(colourName); }
+    wxColour(const wchar_t *colourName) { Init(); Set(colourName); }
 
     // initialization using existing NSColor
     wxColour( WX_NSColor aColor );