don't try to scroll non-existing element into the view, refs #175
Fix scroll in firefox (by specifying an animation on body and html). Fix callback called twice by adding a counter.
Merge branch 'dev-175-non-existing-element' of github.com:fczbkk/bootstrap-tour into develop
Merge branch 'remotes/origin/Firefox-not-scrolling-dev' of github.com:Amli/bootstrap-tour into develop
Updated build