Leave   lowercase when using text-transform (#403)

When using text-transform: uppercase, convert " " back to lowercase " " so that it is recognized as a space by Adobe Acrobat rather than printing out " "

tcpdf.php

@@ -17129,6 +17129,7 @@ class TCPDF {
 							}
 						}
 					}
+					$element = preg_replace("/ /i", " ", $element);
 				}
 				$dom[$key]['value'] = stripslashes($this->unhtmlentities($element));
 			}