Add and improve some debug operator<< functions

Functioning debug operator insertion for RendererLight, LightSources and
Material (both actual objects and nullable pointers).

include/irender.h

@@ -228,9 +228,10 @@ class RendererLight
 };
 typedef std::shared_ptr<RendererLight> RendererLightPtr;
 
+/// Debug stream insertion for RendererLight
 inline std::ostream& operator<< (std::ostream& os, const RendererLight& l)
 {
-    return os << "RendererLight { worldOrigin = " << l.worldOrigin() << " }";
+    return os << "RendererLight(origin=" << l.worldOrigin() << ")";
 }
 
 /**
@@ -286,6 +287,35 @@ class LightSources
     virtual void forEachLight(const RendererLightCallback& callback) const = 0;
 };
 
+/// Debug stream insertion for LightSources
+inline std::ostream& operator<< (std::ostream& s, const LightSources& ls)
+{
+    s << "LightSources(";
+
+    // Insert comma-separated list of RendererLights
+    bool addComma = false;
+    ls.forEachLight(
+        [&](const RendererLight& l)
+        {
+            if (addComma)
+                s << ", ";
+            s << l;
+            addComma = true;
+        }
+    );
+
+    return s << ")";
+}
+
+/// Debug stream insertion for possibly null LightSources pointer
+inline std::ostream& operator<< (std::ostream& s, const LightSources* ls)
+{
+    if (ls)
+        return s << *ls;
+    else
+        return s << "[no lightsources]";
+}
+
 /**
  * \brief
  * A list of lights which might (but don't necessarily) intersect a LitObject

include/ishaders.h

@@ -327,18 +327,26 @@ class Material
 
 typedef std::shared_ptr<Material> MaterialPtr;
 
-/**
- * Stream insertion of Material for debugging purposes.
- */
+/// Stream insertion of Material for debugging purposes.
 inline
-std::ostream& operator<< (std::ostream& os, const Material& shader) {
-	os << "Material { name = " << shader.getName()
-	   << ", filename = " << shader.getShaderFileName()
-	   << ", firstlayer = " << shader.firstLayer()
-	   << " }";
+std::ostream& operator<< (std::ostream& os, const Material& shader)
+{
+	os << "Material(name=" << shader.getName()
+	   << ", filename=" << shader.getShaderFileName()
+	   << ", firstlayer=" << shader.firstLayer()
+	   << ")";
 	return os;
 }
 
+/// Debug stream insertion of possibly null material pointer
+inline std::ostream& operator<< (std::ostream& os, const Material* m)
+{
+    if (m)
+        return os << *m;
+    else
+        return os << "[no material]";
+}
+
 typedef std::function<void(const std::string&)> ShaderNameCallback;
 
 const char* const MODULE_SHADERSYSTEM = "MaterialManager";