Error diffing tables containing UTF-8 characters

[cim--]

Version 0.1.16 fails with an iconv() error when trying to convert a table containing a UTF-8 character with no named html entity equivalent (so e.g. £ is fine but ■ will fail)
Version 0.1.15 works correctly.

Seems to be failing at line 630 of lib/Caxy/HtmlDiff/Table/TableDiff.php on the attempt to convert to iso-8859-1 encoding, possibly as a consequence of the changes for #123

Minimal reproduction

$t = "<table><tr><td>■</td></tr></table>"; 
$t2 = "<table><tr><td>■■</td></tr></table>";
$d = new Caxy\HtmlDiff\HtmlDiff($t, $t2); 
$d->build();

gives
iconv(): Detected an illegal character in input string in vendor/caxy/php-htmldiff/lib/Caxy/HtmlDiff/Table/TableDiff.php on line 630

Thanks

[jurgenhaas]

I'm running into the same issue. Adding the IGNORE option to the destination encoding in iconv resolves that. I'm opening a PR for this.