Test with stuff + Forestry potential support

BM_src/forestry/api/mail/IPostalCarrier.java

@@ -0,0 +1,42 @@
+package forestry.api.mail;
+
+import cpw.mods.fml.relauncher.Side;
+import cpw.mods.fml.relauncher.SideOnly;
+import net.minecraft.item.ItemStack;
+import net.minecraft.util.Icon;
+import net.minecraft.world.World;
+
+/**
+ *  Postal Carriers are systems which can be hooked into Forestry's mail system to handle mail delivery.
+ *  
+ *  The two available carriers in vanilla Forestry are
+ *       "player" - Delivers mail to individual players.
+ *       "trader" - Handles mail addressed to trade stations.
+ */
+public interface IPostalCarrier {
+
+	/**
+	 * @return A lower-case identifier without spaces.
+	 */
+	String getUID();
+	
+	/**
+	 * @return A human-readable name for this carrier.
+	 */
+	String getName();
+	
+	@SideOnly(Side.CLIENT)
+	Icon getIcon();
+
+	/**
+	 * Handle delivery of a letter addressed to this carrier. 
+	 * @param world The world the {@link IPostOffice} handles.
+	 * @param office {link @IPostOffice} which received this letter and handed it to the carrier. 
+	 * @param recipient An identifier for the recipient as typed by the player into the address field.
+	 * @param letterstack ItemStack representing the letter. See {@link IPostRegistry} for helper functions to validate and extract it.
+	 * @param doDeliver Whether or not the letter is supposed to actually be delivered or if delivery is only to be simulated.
+	 * @return {link IPostalState} holding information on success or failure for delivery.
+	 */
+	IPostalState deliverLetter(World world, IPostOffice office, String recipient, ItemStack letterstack, boolean doDeliver);
+
+}