Fixed lava bug

src/tiles/tile.coffee

@@ -10,6 +10,7 @@ class Tile
       )
     
     @currentLayer = 0
+    @empty = false
     @entity = null
     @isActive = false
     @isBuildable = !(Math.round(Math.random()*10) == 5)
@@ -19,15 +20,18 @@ class Tile
     # Some tiles are not buildable
     return unless @isBuildable
 
-    if button == "left"
+    if button == "left" and !@empty
       if (app.game.availableSiloStorage() - app.game.usedSiloStorage()) > 0
         if @layers[@currentLayer].collect()
           name = app.layerIndexToName(@currentLayer)
           app.game.resources[name] += 1
         else
           @currentLayer += 1
+
+          if @currentLayer == allResourceTypes().length-1
             # If we reach the bottom, the entity on top dies.
-          @entity = null if @currentLayer == allResourceTypes().length-1
+            @entity = null
+            @empty = true
 
   tick: ->
     @entity.tick @ if @entity