Enhancements - date

- Relocated valid.cpp/dataValid to Date::valid.
- Added new unit tests in date.t.cpp.

src/Date.cpp

@@ -254,6 +254,22 @@ const std::string Date::toString (const std::string& format /*= "m/d/Y" */) cons
   return formatted;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+bool Date::valid (const std::string& input, const std::string& format)
+{
+  try
+  {
+    Date test (input, format);
+  }
+
+  catch (...)
+  {
+    return false;
+  }
+
+  return true;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 bool Date::valid (const int m, const int d, const int y)
 {