Game url hardcoded into gamelabels.php

[Jorann]

app/lang/en/gamelabels.php contains a hardcoded URL for the game location on crowdtruth.org. This breaks some links when running it somewhere else.

[c-martinez]

app/lang/en/gamelabels.php is meant more for customizing text (welcome messages, etc). Perhaps it would be more suitable to store a URL for communicating with crowdtruth on a config file in app/config/* ?