Implement Harvest Ritual

Currently only a handler for standard crops (wheat, carrots, etc) is implemented.

src/main/java/WayofTime/bloodmagic/api/iface/IHarvestHandler.java

@@ -0,0 +1,30 @@
+package WayofTime.bloodmagic.api.iface;
+
+import WayofTime.bloodmagic.api.BlockStack;
+import net.minecraft.util.BlockPos;
+import net.minecraft.world.World;
+
+/**
+ * Used to define a HarvestHandler for the Harvest Ritual.
+ */
+public interface IHarvestHandler
+{
+    /**
+     * Called whenever the Harvest Ritual attempts to harvest a block.
+     * <br>
+     * Use this to break the block, plant a new one, and drop the produced items.
+     * <br>
+     * Make sure to do checks so you are certain the blocks being handled
+     * are the block types you want.
+     *
+     * @param world
+     *          - The world the {@link WayofTime.bloodmagic.api.ritual.IMasterRitualStone} is in.
+     * @param pos
+     *          - The position of the Block being checked
+     * @param blockStack
+     *          - The Block being checked
+     *
+     * @return If the block was successfully harvested.
+     */
+    boolean harvestAndPlant(World world, BlockPos pos, BlockStack blockStack);
+}