Show wxHtmlCell address in its Dump()

This makes it easier to see which cell is which one when debugging.

Also use GetMaxTotalWidth() instead of GetWidth(), as the former is more
useful for container cells (and the same for the other ones).

src/html/htmlcell.cpp

@@ -292,8 +292,9 @@ wxString wxHtmlCell::GetDescription() const
 wxString wxHtmlCell::Dump(int indent) const
 {
     wxString s(' ', indent);
-    s += wxString::Format("%s at (%d, %d) %dx%d",
-                          GetDescription(), m_PosX, m_PosY, m_Width, m_Height);
+    s += wxString::Format("%s(%p) at (%d, %d) %dx%d",
+                          GetDescription(), this,
+                          m_PosX, m_PosY, GetMaxTotalWidth(), m_Height);
     if ( !m_id.empty() )
         s += wxString::Format(" [id=%s]", m_id);