Make blend mode the default for channel mixing.

mini_al.h

@@ -620,9 +620,10 @@ typedef enum
 
 typedef enum
 {
-    mal_channel_mix_mode_simple = 0,        // Drop excess channels; zeroed out extra channels.
-    mal_channel_mix_mode_planar_blend,    // Simple averaging based on the plane(s) the channel is sitting on.
+    mal_channel_mix_mode_planar_blend = 0,  // Simple averaging based on the plane(s) the channel is sitting on.
+    mal_channel_mix_mode_simple,            // Drop excess channels; zeroed out extra channels.    
     //mal_channel_mix_mode_spatial,         // Blend channels based on spatial locality.
+    mal_channel_mix_mode_default = mal_channel_mix_mode_planar_blend
 } mal_channel_mix_mode;
 
 typedef enum