Enhancements - Config

- Added processing for context.config overrides, and associated
  argc,argv handling.
- Bug fix in filt.t.cpp, but three tests still fail.  Too big a
  distraction to fix right now.
- Warning: build is not broken, but task is broken.

src/Att.cpp

@@ -103,7 +103,8 @@ bool Att::valid (const std::string& input) const
     if (n.skip (':') &&
         (n.getQuoted ('"', ignored) ||
          n.getUntil  (' ', ignored) ||
-         n.getUntilEOS (ignored)))
+         n.getUntilEOS (ignored)    ||
+         n.depleted ()))
       return true;
 
     return false;