Patch - Configurable week start day.

- Added ChangeLog entry.
- Modified timesheet report error message on incorrect weekstart
  value to match that of calendar.

html/task.html

@@ -136,6 +136,8 @@
                   <li>Fixed bug that cause the _forcecolor configuration variable to be
                       considered obsolete (thank to Bruce Dillahunty).
                   <li>Fixed documentation errors (thanks to Thomas@BIC).
+                  <li>The 'weekstart' configuration variable now controls the 'calendar'
+                      command (thanks to Federico Hernandez).
                 </ul>
 
                 <p>