Test with stuff + Forestry potential support

BM_src/forestry/api/mail/ILetter.java

@@ -0,0 +1,53 @@
+package forestry.api.mail;
+
+import java.util.List;
+
+import net.minecraft.inventory.IInventory;
+import net.minecraft.item.ItemStack;
+import forestry.api.core.INBTTagable;
+
+public interface ILetter extends IInventory, INBTTagable {
+
+	ItemStack[] getPostage();
+
+	void setProcessed(boolean flag);
+
+	boolean isProcessed();
+
+	boolean isMailable();
+
+	void setSender(MailAddress address);
+
+	MailAddress getSender();
+
+	boolean hasRecipient();
+
+	void setRecipient(MailAddress address);
+
+	MailAddress[] getRecipients();
+
+	String getRecipientString();
+
+	void setText(String text);
+
+	String getText();
+
+	void addTooltip(List list);
+
+	boolean isPostPaid();
+
+	int requiredPostage();
+
+	void invalidatePostage();
+
+	ItemStack[] getAttachments();
+
+	void addAttachment(ItemStack itemstack);
+
+	void addAttachments(ItemStack[] itemstacks);
+
+	int countAttachments();
+
+	void addStamps(ItemStack stamps);
+
+}