[FIX] HTML elements passed as container produce error

[JekRock]

Currently, selectors only acceptable as a container passed in options. Passing an HTML element produces the error 'Container must either be a selector string or an HTMLElement.'.
It seems like it's a typo here.

Please check out the pull request #21

[JekRock]

I'm sorry for the duplicated PR.
It's already suggested in #18