Merge branch 'hotfix/code128'

Reverts #105

Author: weierophinney

src/Barcode/Code128.php

@@ -180,10 +180,7 @@ public function hasValidCharacters($value)
                     break;
             }
 
-            if (! empty($value) && strlen($value) > 1) {
-                $value = $strWrapper->substr($value, 1, null);
-            }
-
+            $value = $strWrapper->substr($value, 1, null);
             $read  = $set;
         }