Update search in select options

[worldofsites]

Updating search behavior in select options. This update adds the ability to navigate between select options (as it does in a standart select) that matches the regular expression condition after you press the keys. Currently, after you press the keys, you stay only on the first element found. Which is not very convenient.

And also added ability to search for selects with optgroups. Currently it doesn't works for selects with optgroups.