Remove function validate() (?)

[tripu]

https://github.com/tabatkins/password/blob/7e839bb73146dc889c587322472b7165d5bea3d9/index.html#L112-L114

I understand it's not being used; remove?

I didn't realise it was there, and actually re-implemented it in my own fork, a bit differently (I'm using it): https://github.com/tripu/password/blob/gh-pages/index.html#L309-L316