Add info for common unsupported audio types

Pixi/Audio/AudioFakeImporter.cs

@@ -0,0 +1,37 @@
+using System;
+using GamecraftModdingAPI;
+using GamecraftModdingAPI.Utility;
+using Pixi.Common;
+
+namespace Pixi.Audio
+{
+    public class AudioFakeImporter : Importer
+    {
+        public int Priority { get; } = 0;
+        public bool Optimisable { get; } = false;
+        public string Name { get; } = "AudioWarning~Spell";
+        public BlueprintProvider BlueprintProvider { get; } = null;
+        public bool Qualifies(string name)
+        {
+            return name.EndsWith(".flac", StringComparison.InvariantCultureIgnoreCase)
+                || name.EndsWith(".ogg", StringComparison.InvariantCultureIgnoreCase)
+                || name.EndsWith(".mp3", StringComparison.InvariantCultureIgnoreCase)
+                || name.EndsWith(".wav", StringComparison.InvariantCultureIgnoreCase)
+                || name.EndsWith(".aac", StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        public BlockJsonInfo[] Import(string name)
+        {
+            Logging.CommandLogWarning($"Audio importing only works with MIDI (.mid) files, which '{name}' is not.\nThere are many converters online, but for best quality use a MIDI file made from a music transcription.\nFor example, musescore.com has lots of good transcriptions and they offer a 30-day free trial.");
+            return null;
+        }
+
+        public void PreProcess(string name, ref ProcessedVoxelObjectNotation[] blocks)
+        {
+        }
+
+        public void PostProcess(string name, ref Block[] blocks)
+        {
+        }
+    }
+}

Pixi/Common/ColorSpaceUtility.cs

@@ -314,6 +314,7 @@ namespace Pixi.Common
 							count++;
 						}
 					}
+					yield return asyncHandle.Continue();
 		        }
 	        }
         }

Pixi/Common/CommandRoot.cs

@@ -157,7 +157,7 @@ namespace Pixi.Common
 #endif
             // import blocks
             BlockJsonInfo[] blocksInfo = magicImporter.Import(name);
-            if (blocksInfo.Length == 0)
+            if (blocksInfo == null || blocksInfo.Length == 0)
             {
 #if DEBUG
                 Logging.CommandLogError($"Importer {magicImporter.Name} didn't provide any blocks to import. Mission Aborted!");

Pixi/PixiPlugin.cs

@@ -57,6 +57,7 @@ namespace Pixi
 #endif
 			// Audio functionality
 			root.Inject(new MidiImporter());
+			root.Inject(new AudioFakeImporter());
 		}
 	}
 }