Cycles: Cleanup, style and unused arguments

- Some arguments were inapproriatry tagged as unused
  using (void)foo semantic.

  Only use such semantic in tricky casses, when something
  needs to be ignored in release builds or something is
  dependent on tricky ifndef policy.

  For rest of the cases just use void foo(int /bar*/)
  semantic, which ensures variable is not used. Solves
  confusion and code running out of sync with later
  development.

- Used proper unused semantic to some arguments.

- Added braces to make code easier to follow, tricky
  indentation with ifdef, uh.

intern/cycles/render/shader.cpp

@@ -335,11 +335,14 @@ ShaderManager *ShaderManager::create(Scene *scene, int shadingsystem)
 	(void)shadingsystem;  /* Ignored when built without OSL. */
 
 #ifdef WITH_OSL
-	if(shadingsystem == SHADINGSYSTEM_OSL)
+	if(shadingsystem == SHADINGSYSTEM_OSL) {
 		manager = new OSLShaderManager();
+	}
 	else
 #endif
+	{
 		manager = new SVMShaderManager();
+	}
 	
 	add_default(scene);