small fix 0223

1 Add minimap icons for some of the mobs, e.g. birds, worms in the mine, giant turtles. Now you can see them on minimap from long distance.
2 Pears can be put into grocery shelves now.
3 The spider cocoons can be harvested with pickaxe now, but there is nothing valuable there, just for destroying them to prevent the boss spider from healing itself.
4 The cave trees can be chopped down now, but they only drop some wood blocks.