[RFR] Make validation behave the same in creation and edition forms

Validation used to behave differently in creation and edition form, even though the validation rules were the same. This proved confusing for users.

Moving to another strategy: validation status isn't showed unless the user updates the input. Works the same for both edition and creation form.

![image](https://cloud.githubusercontent.com/assets/99944/5544083/bcd0b682-8aff-11e4-99a7-6db1c6f9e462.png)

And while I was at it, I added basic e2e tests of the feature. It showed that the way pages were fetched in previous e2e tests didn't work - we need to use a beforeEach(). So I refactored those, too.