add handlers to catch validation errors (specifically arrays)

[jessefulton]

If I had an "isInt" validator in my route, but the request came through as an array, the request would hang and eventually time out/500. For example, I had a

    server.get
        url: "/posts"
        swagger:
            summary: "Get posts"
            notes: "..."
            nickname: "Get posts"
        validation:
            before:
                isRequired: false
                isInt: true
                scope: "query"

When called with /posts?before=12345&before=123456, the server would hang. This should address that issue, although I didn't add a ton of test cases...