Merge pull request #296 from Dmitry-Me/assertForImpossibleCase

Assert for impossible case
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 91aa756..6d8573b 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -346,8 +346,9 @@
         case 1:

             --output;

             *output = (char)(input | FIRST_BYTE_MARK[*length]);

-        default:

             break;

+        default:

+            TIXMLASSERT( false );

     }

 }