Performance

- Added Timer class to display high resolution timing information.
- Found terrible bug in Table::optimize that was taking up 99.7%,
  on average, of the Table::rendering time, including sorting.  This
  fix naturally causes a 187-fold speedup of rendering.
- Changed report.cpp in handleCustomReport to only load pending tasks,
  instead of all pending tasks.  Subtle, but important difference.

src/Timer.cpp

@@ -0,0 +1,56 @@
+////////////////////////////////////////////////////////////////////////////////
+// task - a command line task list manager.
+//
+// Copyright 2006 - 2009, Paul Beckingham.
+// All rights reserved.
+//
+// This program is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free Software
+// Foundation; either version 2 of the License, or (at your option) any later
+// version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+// details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program; if not, write to the
+//
+//     Free Software Foundation, Inc.,
+//     51 Franklin Street, Fifth Floor,
+//     Boston, MA
+//     02110-1301
+//     USA
+//
+////////////////////////////////////////////////////////////////////////////////
+#include <iostream>
+#include <iomanip>
+#include <Timer.h>
+
+////////////////////////////////////////////////////////////////////////////////
+// Timer starts when the object is constructed.
+Timer::Timer (const std::string& description)
+: mDescription (description)
+{
+  ::gettimeofday (&mStart, NULL);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Timer stops when the object is desctructed.
+Timer::~Timer ()
+{
+  struct timeval end;
+  ::gettimeofday (&end, NULL);
+
+  std::cout << "Timer "
+            << mDescription
+            << " "
+            << std::setprecision (6)
+            << ((end.tv_sec - mStart.tv_sec) +
+               ((end.tv_usec - mStart.tv_usec ) / 1000000.0))
+            << std::endl;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+