Enhancements - Cmd object

- New Cmd object to handle localized commands, customReports and general
  command parsing.
- Localized new Subst methods.
- Relocate guess method from parse.cpp to text.cpp.
- Converted Att object to use new valid/parse scheme.
- Unit tests for Cmd object.
- Fixed att.t.cpp unit tests.

src/i18n.h

@@ -25,6 +25,17 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
+////////////////////////////////////////////////////////////////////////////////
+//
+// Strings that should be localized:
+//   - All text output that the user sees or types
+//
+// Strings that should NOT be localized:
+//   - ./taskrc configuration variable names
+//   - certain literals associated with parsing
+//
+////////////////////////////////////////////////////////////////////////////////
+
 #ifndef INCLUDED_I18N
 #define INCLUDED_I18N