restructure conversation item classes

briar-android/src/org/briarproject/android/contact/ConversationMessageInItem.java

@@ -0,0 +1,32 @@
+package org.briarproject.android.contact;
+
+import org.briarproject.api.messaging.PrivateMessageHeader;
+
+// This class is not thread-safe
+public class ConversationMessageInItem extends ConversationMessageItem
+		implements ConversationItem.IncomingItem {
+
+	private boolean read;
+
+	public ConversationMessageInItem(PrivateMessageHeader header) {
+		super(header);
+
+		read = header.isRead();
+	}
+
+	@Override
+	int getType() {
+		return MSG_IN;
+	}
+
+	@Override
+	public boolean isRead() {
+		return read;
+	}
+
+	@Override
+	public void setRead(boolean read) {
+		this.read = read;
+	}
+
+}