Merge the matrix-java-sdk due to it no longer maintained. Remove thirdparty repositories.

src/main/java/io/kamax/matrix/codec/MxBase64.java

@@ -0,0 +1,36 @@
+/*
+ * matrix-java-sdk - Matrix Client SDK for Java
+ * Copyright (C) 2017 Kamax Sarl
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.matrix.codec;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+public class MxBase64 {
+
+    public static String encode(byte[] data) {
+        return Base64.getEncoder().withoutPadding().encodeToString(data);
+    }
+
+    public static String encode(String data) {
+        return encode(data.getBytes(StandardCharsets.UTF_8));
+    }
+
+}