Config - defaults

- Config is now providing a default set of all configuration variables.
- The default set is used to both initialize a Config object, and to
  create a sample .taskrc.

src/tests/delete.t

@@ -34,6 +34,7 @@ use Test::More tests => 17;
 if (open my $fh, '>', 'delete.rc')
 {
   print $fh "data.location=.\n",
+            "confirmation=no\n",
             "echo.command=no\n";
   close $fh;
   ok (-r 'delete.rc', 'Created delete.rc');