Bug 452 - Need relative date value 'now' to fully support times

- Added 'now' as a relative date.
- Modified 'overdue' report to use 'now' instead of 'today' as the
  distinction between due and overdue.

src/tests/date.t.cpp

@@ -34,7 +34,7 @@ Context context;
 ////////////////////////////////////////////////////////////////////////////////
 int main (int argc, char** argv)
 {
-  UnitTest t (150);
+  UnitTest t (154);
 
   try
   {
@@ -49,6 +49,13 @@ int main (int argc, char** argv)
     t.ok    (now       >= yesterday, "now >= yesterday");
     t.ok    (now       >  yesterday, "now > yesterday");
 
+    // Date::Date ("now")
+    Date relative_now ("now");
+    t.ok (relative_now.sameHour (now),  "Date ().sameHour (Date (now))");
+    t.ok (relative_now.sameDay (now),   "Date ().sameDay (Date (now))");
+    t.ok (relative_now.sameMonth (now), "Date ().sameMonth (Date (now))");
+    t.ok (relative_now.sameYear (now),  "Date ().sameYear (Date (now))");
+
     // Loose comparisons.
     Date left ("7/4/2008");
     Date comp1 ("7/4/2008");