fix bug that return empty “where object” if filter contains utf8letter

[likegun]

In find method, if (expression.match(/(([\w|.]+)\s(\w+)\s([\w|\s|%|_]+),?)+/)), if expression contains utf8letters the if condition would be false and return empty where object.

[ricmalta]

@likegun Did you have any chance to have a look to my feedback? thank you