Breaks when string contains a zero-width character

[carbontwelve]

When using the isConfusable method with the input string www.microsоft.com and a preferredAliases of ['latin']. The following error is returned: Undefined Index: Confusable.php:146.

This is because the input string contains the zero-width character \u65279 - incidentally this zero width character gets correctly parsed as the common alias however on line 146 of Confusable.php it's essentially a empty string and the array key lookup fails on the index not existing.

If the index does exist in the json source, then maybe it needs converting so the index is the escaped unicode in ASCII string form - if so this can be folded into #1.

[carbontwelve]

Looks as though the port was 100%; the Python source uses the dictionary get method on the loaded json source which returns a sane default.

By wrapping the assignment of $found on line 146 (now 148 after comments) with an isset check and assigning an empty array by default this issue is fixed.

[carbontwelve]

Fixed by #3