Missing files from previous commit

Cavern.Format/Common/KeyLengthValue.cs

@@ -2,6 +2,8 @@
 using System.IO;
 using System.Text;
 
+using Cavern.Format.Utilities;
+
 namespace Cavern.Format.Common {
     /// <summary>
     /// A tag and its data encoded in the format of a key, a length, and a value, most notably used in the EBML format.

Cavern.Format/Common/_Exceptions.cs

@@ -37,6 +37,18 @@ public class DecoderException : Exception {
         public DecoderException(int errorCode) : base(string.Format(message, errorCode)) { }
     }
 
+    /// <summary>
+    /// Tells that no program was detected in the container/track.
+    /// </summary>
+    public class NoProgramException : Exception {
+        const string message = "No program was detected.";
+
+        /// <summary>
+        /// Tells that no program was detected in the container/track.
+        /// </summary>
+        public NoProgramException() : base(message) { }
+    }
+
     /// <summary>
     /// Tells that a decoder which can process an infinite stream is not able to return content length.
     /// </summary>

Cavern.Format/Container/Matroska/Block.cs

@@ -1,6 +1,7 @@
 using System.IO;
 
 using Cavern.Format.Common;
+using Cavern.Format.Utilities;
 using Cavern.Utilities;
 
 namespace Cavern.Format.Container.Matroska {