Handle missing steps

[akrohn]

Hello, nice plugin.

Currently it behaves strange, when steps are missing, for instance 1,2,4

This can occur, when some functionality of a page is depending on the role of a user that logs in. So some steps are optional.

Cheers.

P.S: Mentioning intro.js doesn't hurt ;)

[clu3]

This will be the first bug i'll fix this weekend. I was trying to handle that when I first wrote it but it required a little tweak so I kinda stopped there. Please hold.