Allow calling wxListCtrl::SetImageList() before Create() in wxMSW

This already worked with the generic version, but silently failed with
wxMSW, so make it work with wxMSW too as it doesn't cost much and makes
wxListCtrl behave in the same way under all platforms.

Also document that SetImageList() can be used before the window is
created.

interface/wx/listctrl.h

@@ -1110,6 +1110,11 @@ public:
         This method does not take ownership of the image list, you have to
         delete it yourself.
 
+        Note that, unlike for most of the other methods of this class, it is
+        possible to call this function before the corresponding window is
+        created, i.e. do it in a constructor of a class derived from wxListCtrl
+        before calling Create().
+
         @see AssignImageList()
     */
     void SetImageList(wxImageList* imageList, int which);

src/msw/listctrl.cpp

@@ -320,6 +320,15 @@ bool wxListCtrl::Create(wxWindow *parent,
     if ( HasFlag(wxLC_LIST) )
         m_colCount = 1;
 
+    // If SetImageList() had been called before the control was created, take
+    // it into account now.
+    if ( m_imageListNormal )
+        ListView_SetImageList(GetHwnd(), GetHimagelistOf(m_imageListNormal), LVSIL_NORMAL);
+    if ( m_imageListSmall )
+        ListView_SetImageList(GetHwnd(), GetHimagelistOf(m_imageListSmall), LVSIL_SMALL);
+    if ( m_imageListState )
+        ListView_SetImageList(GetHwnd(), GetHimagelistOf(m_imageListState), LVSIL_STATE);
+
     return true;
 }
 
@@ -1551,6 +1560,13 @@ void wxListCtrl::SetImageList(wxImageList *imageList, int which)
         m_imageListState = imageList;
         m_ownsImageListState = false;
     }
+
+    // It's possible that this function is called before the control is
+    // created, don't do anything else in this case -- the image list will be
+    // really set after creating it.
+    if ( !GetHwnd() )
+        return;
+
     (void) ListView_SetImageList(GetHwnd(), (HIMAGELIST) imageList ? imageList->GetHIMAGELIST() : 0, flags);
 
     // For ComCtl32 prior 6.0 we need to re-assign all existing