Add handlers for "tall" and "stem" crops

Documentation for all harvest-y stuff as well.

src/main/java/WayofTime/bloodmagic/ritual/harvest/HarvestHandlerTall.java

@@ -0,0 +1,58 @@
+package WayofTime.bloodmagic.ritual.harvest;
+
+import WayofTime.bloodmagic.api.BlockStack;
+import WayofTime.bloodmagic.api.iface.IHarvestHandler;
+import WayofTime.bloodmagic.api.registry.HarvestRegistry;
+import net.minecraft.entity.item.EntityItem;
+import net.minecraft.init.Blocks;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.BlockPos;
+import net.minecraft.world.World;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Harvest handler for crops that grow vertically such as
+ * Sugar Cane and Cactus.
+ * <br>
+ * Register a new crop for this handler with
+ * {@link HarvestRegistry#registerTallCrop(BlockStack)}
+ */
+public class HarvestHandlerTall implements IHarvestHandler
+{
+    public HarvestHandlerTall()
+    {
+        HarvestRegistry.registerTallCrop(new BlockStack(Blocks.reeds));
+        HarvestRegistry.registerTallCrop(new BlockStack(Blocks.cactus));
+    }
+
+    @Override
+    public boolean harvestAndPlant(World world, BlockPos pos, BlockStack blockStack)
+    {
+        boolean retFlag = false;
+
+        List<ItemStack> drops = new ArrayList<ItemStack>();
+        if (HarvestRegistry.getTallCrops().contains(blockStack))
+        {
+            BlockStack up = BlockStack.getStackFromPos(world, pos.up());
+            if (up.equals(blockStack))
+            {
+                drops = up.getBlock().getDrops(world, pos.up(), up.getState(), 0);
+                world.destroyBlock(pos.up(), false);
+                retFlag = true;
+            }
+        }
+
+        if (!world.isRemote)
+        {
+            for (ItemStack drop : drops)
+            {
+                EntityItem item = new EntityItem(world, pos.getX(), pos.getY() + 0.5, pos.getZ(), drop);
+                world.spawnEntityInWorld(item);
+            }
+        }
+
+        return retFlag;
+    }
+}