Add Aaru as creator for Apple 2MG disk images.

Aaru.Images/Apple2MG/Constants.cs

@@ -67,9 +67,13 @@ namespace Aaru.DiscImages
         /// </summary>
         const uint CREATOR_CIDER = 0x50726443;
         /// <summary>
-        ///     Disk image created by Aaru, "dic "
+        ///     Disk image created by DiscImageChef, "dic "
         /// </summary>
         const uint CREATOR_DIC = 0x20636964;
+        /// <summary>
+        ///     Disk image created by Aaru, "aaru"
+        /// </summary>
+        const uint CREATOR_AARU = 0x75726161;
 
         const    uint  LOCKED_DISK         = 0x80000000;
         const    uint  VALID_VOLUME_NUMBER = 0x00000100;

Aaru.Images/Apple2MG/Read.cs

@@ -183,6 +183,9 @@ namespace Aaru.DiscImages
                 case CREATOR_DIC:
                     imageInfo.Application = "DiscImageChef";
                     break;
+                case CREATOR_AARU:
+                    imageInfo.Application = "Aaru";
+                    break;
                 default:
                     imageInfo.Application = $"Unknown creator code \"{Encoding.ASCII.GetString(creator)}\"";
                     break;

Aaru.Images/Apple2MG/Write.cs

@@ -170,7 +170,7 @@ namespace Aaru.DiscImages
             imageHeader = new A2ImgHeader
             {
                 Blocks     = (uint)(imageInfo.Sectors * imageInfo.SectorSize) / 512,
-                Creator    = CREATOR_DIC,
+                Creator    = CREATOR_AARU,
                 DataOffset = 0x40,
                 DataSize   = (uint)(imageInfo.Sectors * imageInfo.SectorSize),
                 Flags =