[cnc] inftry detect cloaked in next tile(C&C orig)

Infantry can detect cloaked units in the next tile. This behaviour was in the original C&C Gold.
(Even though it says range=2, it is actually just in the next tile)

Fixed GrenadierExplode.
Merge pull request #2672 from psydev/patch-48

[cnc] inftry detect cloaked in next tile(C&C orig)