Add methods and hooks to PrivateGroupManager related to members and removal

briar-api/src/org/briarproject/api/privategroup/GroupMember.java

@@ -0,0 +1,35 @@
+package org.briarproject.api.privategroup;
+
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.Author.Status;
+import org.briarproject.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class GroupMember {
+
+	private final Author author;
+	private final Status status;
+	private final boolean shared;
+
+	public GroupMember(Author author, Status status, boolean shared) {
+		this.author = author;
+		this.status = status;
+		this.shared = shared;
+	}
+
+	public Author getAuthor() {
+		return author;
+	}
+
+	public Status getStatus() {
+		return status;
+	}
+
+	public boolean isShared() {
+		return shared;
+	}
+
+}