Bug Fix - recurrence

- Fixed bug whereby handleRecurrence was being called after the tasks
  were loaded and filtered, and thus handleRecurrence operated on a
  filtered set, and failed.  The fix is to move the call to before the
  TDB::load call, and to add another TDB::loadPending call inside
  handleRecurrence.  This means TDB::load needs to be reentrant without
  re-reading the file, and can therefore be called twice, with the
  likelihood of there being a different filter for each call.  This in
  turn led to the problem whereby handleRecurrence would generate the
  synthetic tasks, which then sat uncommitted in TDB::mNew.  The fix
  for this is that every call to TDB::loadPending gets the contents of
  TDB::mNew appended (with correct IDs).  This bug is what you might
  call a good one.

src/main.h

@@ -49,7 +49,7 @@ void gatherNextTasks (std::vector <Task>&, std::vector <int>&);
 void onChangeCallback ();
 
 // recur.cpp
-void handleRecurrence (std::vector <Task>&);
+void handleRecurrence ();
 Date getNextRecurrence (Date&, std::string&);
 bool generateDueDates (Task&, std::vector <Date>&);
 void updateRecurrenceMask (std::vector <Task>&, Task&);