Merge branch '0.9.4' of https://github.com/g-truc/glm into 0.9.4

glm/gtc/quaternion.inl

@@ -707,6 +707,10 @@ namespace detail
 			Result.y = (m[1][2] + m[2][1]) * mult;
 			Result.z = biggestVal;
 			break;
+			
+        default:                // Silence a -Wswitch-default warning in GCC. Should never actually get here. Assert is just for sanity.
+            assert(false);
+            break;
 		}
 		return Result;
 	}