Shadow File Rewrite

- No longer writes shadow files based on TDB onChange trigger.
- Addressed bug whereby adding a recurring task trigger a shadow
  file rewrite, which in turn performs trigger another rewrite...

src/TDB.cpp

@@ -308,7 +308,6 @@ bool TDB::overwritePending (std::vector <T>& all)
       fputs (it->compose ().c_str (), out);
 
     fclose (out);
-    dbChanged ();
     return true;
   }
 
@@ -329,7 +328,6 @@ bool TDB::writePending (const T& t)
     fputs (t.compose ().c_str (), out);
 
     fclose (out);
-    dbChanged ();
     return true;
   }
 
@@ -350,8 +348,6 @@ bool TDB::writeCompleted (const T& t)
     fputs (t.compose ().c_str (), out);
 
     fclose (out);
-    // Note: No call to dbChanged here because this call never occurs by itself.
-    //       It is always accompanied by an overwritePending call.
     return true;
   }
 
@@ -436,20 +432,4 @@ int TDB::nextId ()
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void TDB::onChange (void (*callback)())
-{
-  if (callback)
-    mOnChange.push_back (callback);
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// Iterate over callbacks.
-void TDB::dbChanged ()
-{
-  foreach (i, mOnChange)
-    if (*i)
-      (**i) ();
-}
-
-////////////////////////////////////////////////////////////////////////////////