Add "redirector" property on "FormRequest"

Adding missing "redirector" property, that is accessed from "FormRequest::setRedirector" method. This would allow to have correct IDE auto-complete on that property within that class.
Cleaning up some methods.
Merge pull request #5983 from aik099/add-redirector-property-on-form-request

[5.0] Add "redirector" Property On "FormRequest"
Merge pull request #1 from laravel/master

Master