Find missing tiles

			foreach (var frame in originalTileset)
			{
				var found = false;

				foreach (var tile in ourTileset)
				{
					var match = true;

					for (var i = 0; i < tile.Data.Length; i++)
					{
						if (frame.Data[i] != tile.Data[i])
							match = false;
					}

					if (match)
					{
						found = true;
						break;
					}
				}

				if (!found)
					missing.Add(frame);
			}