Travis CI: site documentation update at 2014-12-13 16:35:30 UTC.

Commit: https://github.com/urho3d/Urho3D/commit/7318006d835fb1efb8e8dfc350ed26a3e519642f

Message: Fix UI element drags with DragDropContent defined showing a "not accepted" icon, yet succeeding when the drag is released.