cItemGrid: Allocate storage lazily (cuberite#4083)

* cItemGrid: Allocate storage lazily
* cItemGrid: Fix spelling, Prioritary -> Priority

Server/Plugins/APIDump/APIDesc.lua

@@ -7213,7 +7213,7 @@ This class represents a 2D array of items. It is used as the underlying storage
 							IsOptional = true,
 						},
 						{
-							Name = "PrioritarySlot",
+							Name = "PrioritySlot",
 							Type = "number",
 							IsOptional = true,
 						},
@@ -7224,7 +7224,7 @@ This class represents a 2D array of items. It is used as the underlying storage
 							Type = "number",
 						},
 					},
-					Notes = "Adds as many items out of ItemStack as can fit. If AllowNewStacks is set to false, only existing stacks can be topped up. If AllowNewStacks is set to true (default), empty slots can be used for the rest. If PrioritarySlot is set to a non-negative value, then the corresponding slot will be used first (if empty or compatible with added items). If PrioritarySlot is set to -1 (default), regular order applies. Returns the number of items that fit.",
+					Notes = "Adds as many items out of ItemStack as can fit. If AllowNewStacks is set to false, only existing stacks can be topped up. If AllowNewStacks is set to true (default), empty slots can be used for the rest. If PrioritySlot is set to a non-negative value, then the corresponding slot will be used first (if empty or compatible with added items). If PrioritySlot is set to -1 (default), regular order applies. Returns the number of items that fit.",
 				},
 				AddItems =
 				{
@@ -7240,7 +7240,7 @@ This class represents a 2D array of items. It is used as the underlying storage
 							IsOptional = true,
 						},
 						{
-							Name = "PrioritarySlot",
+							Name = "PrioritySlot",
 							Type = "number",
 							IsOptional = true,
 						},
@@ -7251,7 +7251,7 @@ This class represents a 2D array of items. It is used as the underlying storage
 							Type = "number",
 						},
 					},
-					Notes = "Same as AddItem, but works on an entire list of item stacks. The a_ItemStackList is modified to reflect the leftover items. If a_AllowNewStacks is set to false, only existing stacks can be topped up. If AllowNewStacks is set to true, empty slots can be used for the rest. If PrioritarySlot is set to a non-negative value, then the corresponding slot will be used first (if empty or compatible with added items). If PrioritarySlot is set to -1 (default), regular order applies. Returns the total number of items that fit.",
+					Notes = "Same as AddItem, but works on an entire list of item stacks. The a_ItemStackList is modified to reflect the leftover items. If a_AllowNewStacks is set to false, only existing stacks can be topped up. If AllowNewStacks is set to true, empty slots can be used for the rest. If PrioritySlot is set to a non-negative value, then the corresponding slot will be used first (if empty or compatible with added items). If PrioritySlot is set to -1 (default), regular order applies. Returns the total number of items that fit.",
 				},
 				ChangeSlotCount =
 				{

src/CMakeLists.txt

@@ -118,6 +118,7 @@ SET (HDRS
 	Inventory.h
 	Item.h
 	ItemGrid.h
+	LazyArray.h
 	LightingThread.h
 	LineBlockTracer.h
 	LinearInterpolation.h