quest: Allow in site answers for quest of typ TYPE_CHECKER
quest: Use id when comparing user quest with current quest

I don't know the reason why comparing objects fails. Printing
user.current_quest and quest shows the same values. It may only be
connected to the Final Quest setup (or a TYPE_CHECKER quest); there
haven't been issues with Weekly Quests (TYPE_CLASSIC quests).
Merge pull request #417 from razvand/master

Lgtm, please deploy.