Allow role=tab for button & input[type=button]
Allow role=tab for button & input[type=button]

Fixes https://github.com/validator/validator/issues/380 Thanks @stevefaulkner

tripu/validator,takenspc/validator,tripu/validator,takenspc/validator,tripu/validator,validator/validator,takenspc/validator,tripu/validator,takenspc/validator,validator/validator,validator/validator,tripu/validator,validator/validator,takenspc/validator,validator/validator