Add severity for validation result

[Angelo]

The issue #5 seems implemented this idea

But it seems that we should the proper HTML like this:

templates.push({ id: "addusernameValidation", 
                    content: "<i class=\"icon icon__error\"></i>Username must not be 'b'"});

IMHO, I think we should avoid writting HTML and do like this:

templates.push({ id: "addusernameValidation", 
                    content: "Username must not be 'b'"},
severity:Severity.Error);

[Rob Stryker]

I agree, which is why we had this change:

• b01752d - Change validator signature to allow separation of error, warning, info, or other (4 weeks ago)