[select]: added passing tabindex to button block

Fixes #1174
[select]: specs for tabindex
Merge pull request #1175 from zxqfox/feature/select-tabindex

added passing tabindex to button block
[image] div => span in tmpl-specs

Fixes #1192
[select] fixup tabindex tests according to button aria-hidden
Merge pull request #1193 from zxqfox/hotfix/image-tests

Hotfix/image tests