Outdated Class 'formErrorOuter' used.

Fixes #836 #824 #834

Using the `.formErrorOuter` class was targeting the prompt incorrectly, causing to not disappear properly and never reappear. Using `.formError` corrects this.

Also, a minor update to the `.fadeTo()` functions used to hide prompts. This sets the opacity to 0 on all (three) uses of the function.