Separate 'no from" from "invalid from"

[goatwriter]

Updated your code to separate feedback:

// From is always required
    if ( empty($input['from']) ) {
      $this->validation[0]['error'] = 'Your email address is required';

    } elseif (! filter_var($input['from'], FILTER_VALIDATE_EMAIL)){
      $this->validation[0]['error'] = 'Please check your email address';
    }