Add an example of a rule with a param and a depends

[ryleyb]

As discussed over at jquery-validation/jquery-validation#451

Needed an example of how rules with parameters work.

[jzaefferer]

Thank you for the contribution. This is mostly looking good. The only problem I see with the example is that you shouldn't need the depend in this case, since an empty, non-required field will not enforce the minlength option either.

[jzaefferer]

I've adjusted the example to use something where the depends actually makes the difference. Its now live on http://jqueryvalidation.org/validate#rules