Columns - mask, imask, parent

- Implemented column objects for the mask, imask and parent attributes.
  Why not.

src/columns/ColParent.h

@@ -0,0 +1,51 @@
+////////////////////////////////////////////////////////////////////////////////
+// taskwarrior - a command line task list manager.
+//
+// Copyright 2006 - 2011, Paul Beckingham, Federico Hernandez.
+// 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
+//
+////////////////////////////////////////////////////////////////////////////////
+#ifndef INCLUDED_COLPARENT
+#define INCLUDED_COLPARENT
+#define L10N                                           // Localization complete.
+
+#include <vector>
+#include <string>
+#include <Column.h>
+#include <Color.h>
+#include <Task.h>
+
+class ColumnParent : public Column
+{
+public:
+  ColumnParent ();
+  ~ColumnParent ();
+
+  bool validate (std::string&);
+  void measure (Task&, int&, int&);
+  void render (std::vector <std::string>&, Task&, int, Color&);
+
+private:
+};
+
+#endif
+////////////////////////////////////////////////////////////////////////////////