Required fields without pos set cause no error

[Leon Pegg]

example = function () {
var params = ducky.params("config", arguments, {
scope: {
valid: "boolean"
},
key: {
valid: /^[a-z][a-z0-9_]*$/
},
value: {
def: undefined,
valid: "object"
},
force: {
req: true,
valid: "boolean"
}
});
}