#13 H::T::E - Add string concat op (.)

[Doug Bell]

Blurring the line a bit more...

Changed lines -
37: | /[-+*\/%.]/ { [ 'BIN_OP',
$item[1] ] } # Added . to be recognized
307: if ($op eq '.') {push @stack, $lhs . $rhs;
next; } # Added evaluation