add function that turns writer version into string

src/OpenMesh/Core/IO/OMFormat.cc

@@ -113,6 +113,19 @@ namespace OMFormat {
     return hdr;
   }
 
+//-----------------------------------------------------------------------------
+
+
+  std::string as_string(uint8 version)
+  {
+    std::stringstream ss;
+    ss << major_version(version);
+    ss << ".";
+    ss << minor_version(version);
+    return ss.str();
+  }
+
+
 //-----------------------------------------------------------------------------
 
   const char *as_string(Chunk::Entity e)