Multiple default scopes

[cziegenberg]

The idea of default scopes is good in some situations, but if you really use scopes, you have multiple scopes that are assigned as default.

At the moment only one scope can be set as default. It would be possible to set an array, because the parameters are not checked, but the scripts calling this method expect an string at the moment.

[alexbilbie]

Good suggestion, I'll add it in the next release

[cziegenberg]

I think the check you added for #43

if ($this->authServer->scopeParamRequired() === true && $this->authServer->getDefaultScope() === null && count($scopes) === 0) {

needs to be changed, because you can also have an enpty string or empty array or better: check the value in "setDefaultScope" and keep the null if empty.