fixed misplacing a Grill deletes it from the inventory.
If a Grill is misplaced, the Grill block is not added to the world
but the item is removed from the players inventory (some conditions).
I also moved the first checkSides to the inner 'if' since it is not
relevant for the second 'if'.

Something to think about: should the conditions to place a Grill also be
checked after it was placed, that is, should the Grill be dropped if one
of the blocks needed to place it is removed?
Merge pull request #637 from CHeuberger/FixMisplacedGrill

fixed misplacing a Grill deletes it from the inventory.