[2.0] Disallow non-primitive values for query parameters

[franzliedke]

Right now, we rely on Rails' to_param to pre-serialize values for use in query strings. That means, things like arrays ([1, 2]) are turned into strings separated by slashes ("1/2"). That is very arbitrary and should not be Restify's concern.

Let's disallow these cases (needs a clear definition of what cases are allowed).

This would be a subtle, but impact-ful BC break, so I would propose to target this for 2.0.