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/tests/.gitignore

@@ -14,3 +14,4 @@ stringtable.t
 nibbler.t
 subst.t
 filt.t
+cmd.t