Undefined offset in transform handler

[bsweeney]

PHP Notice:  Undefined offset: 0 in .../phenx/php-svg-lib/src/Svg/Tag/AbstractTag.php on line 146                                                                                                                                   
PHP Warning:  count(): Parameter must be an array or an object that implements Countable in .../phenx/php-svg-lib/src/Svg/Tag/AbstractTag.php on line 146

caused by preg_match_all that doesn't match and

...
146   if (count($match[0])) {
...

Originally posted by @zacek in https://github.com/PhenX/php-svg-lib/issues/40#issuecomment-401018094