Add missing documentation

reported by the Author tests. Remove undocumented subroutines that
weren't used anywhere.

lib/Karel/Parser.pm

@@ -154,8 +154,6 @@ __DSL__
 $dsl .= join "\n", map "$_ ~ '$terminals{$_}'", keys %terminals;
 
 
-has parser => ( is => 'ro' );
-
 has _grammar => ( is => 'lazy' );
 
 sub _dsl { $dsl }

lib/Karel/Robot.pm

@@ -168,6 +168,12 @@ sub load_grid {
     };
 }
 
+=item my $parser = $robot->parser
+
+An instance of L<Karel::Parser> used to parse the source code.
+
+=cut
+
 has parser => ( is      => 'ro',
                 default => sub { 'Karel::Parser'->new },
 );
@@ -209,6 +215,15 @@ sub learn {
     }
 }
 
+=item $robot->knowledge
+
+All the commands the robot knows. Returns a hash reference, the
+commands are the keys, the values are array references [prog, code]
+where I<prog> is the bytecode corresponding to the command and I<code>
+is the source code.
+
+=cut
+
 has knowledge => ( is => 'rwp' );
 
 =back

lib/Karel/Robot/WithGrid.pm

@@ -31,6 +31,7 @@ use constant {
     FINISHED_DELAYED => 2,
     QUIT             => -1,
 };
+use namespace::clean;
 use Moo::Role;
 requires qw{ set_grid knows };
 
@@ -196,6 +197,11 @@ sub facing {
     $self->grid->at($self->facing_coords)
 }
 
+=item $robot->is_running
+
+Returns true if the robot is running a command, false otherwise.
+
+=cut
 
 has _stack => ( is        => 'rwp',
                 predicate => 'is_running',