Added ResourceListenerWrapper

This class wraps the call to
Resource::AddResourceListener/RemoveResourceListener using RAII and help
a lot with some of the dependencies.
Thanks to this, the render queues now handle their resources listening
properly.

Former-commit-id: 7f215ffa4ccadcc4f44f777656970e92ce01087a

src/Nazara/Utility/SimpleTextDrawer.cpp

@@ -8,17 +8,12 @@
 
 NzSimpleTextDrawer::NzSimpleTextDrawer() :
 m_color(NzColor::White),
+m_fontListener(this),
 m_style(nzTextStyle_Regular)
 {
 	SetFont(NzFont::GetDefault());
 }
 
-NzSimpleTextDrawer::~NzSimpleTextDrawer()
-{
-	if (m_font)
-		m_font->RemoveResourceListener(this);
-}
-
 const NzRectui& NzSimpleTextDrawer::GetBounds() const
 {
 	if (!m_glyphUpdated)
@@ -63,12 +58,8 @@ void NzSimpleTextDrawer::SetColor(const NzColor& color)
 
 void NzSimpleTextDrawer::SetFont(NzFont* font)
 {
-	if (m_font)
-		m_font->RemoveResourceListener(this);
-
 	m_font = font;
-	if (m_font)
-		m_font->AddResourceListener(this);
+	m_fontListener = font;
 
 	m_glyphUpdated = false;
 }