Add OMEMO support

This commit adds the modules smack-omemo and smack-omemo-signal.
smack-omemo is licensed under the Apache license like the rest of the smack project.
smack-omemo-signal on the other hand is licensed under the GPLv3.
Due to the fact, that smack-omemo is not of much use without smack-omemo-signal,
the OMEMO feature can currently only be used by GPLv3 compatible software.
This may change in the future, when a more permissively licensed module becomes available.

Fixes SMACK-743.

smack-omemo-signal-integration-test/.gitignore

@@ -0,0 +1 @@
+int_test_omemo_store/

smack-omemo-signal-integration-test/build.gradle

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+apply plugin: 'application'
+
+description = """\
+Smack integration tests for OMEMO using libsignal."""
+
+mainClassName = 'org.igniterealtime.smack.inttest.smack_omemo_signal.SmackOmemoSignalIntegrationTestFramework'
+applicationDefaultJvmArgs = ["-enableassertions"]
+
+dependencies {
+	compile project(':smack-integration-test')
+	compile project(':smack-omemo-signal')
+}
+
+run {
+	// Pass all system properties down to the "application" run
+	systemProperties System.getProperties()
+}

smack-omemo-signal-integration-test/src/main/java/org/igniterealtime/smack/inttest/smack_omemo_signal/SmackOmemoSignalIntegrationTestFramework.java

@@ -0,0 +1,52 @@
+/**
+ *
+ * Copyright 2017 Paul Schaub
+ *
+ * This file is part of smack-omemo-signal-integration-test.
+ *
+ * smack-omemo-signal-integration-test is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+ */
+package org.igniterealtime.smack.inttest.smack_omemo_signal;
+
+import org.igniterealtime.smack.inttest.SmackIntegrationTestFramework;
+import org.jivesoftware.smack.SmackException;
+import org.jivesoftware.smack.XMPPException;
+import org.jivesoftware.smackx.omemo.exceptions.CorruptedOmemoKeyException;
+import org.jivesoftware.smackx.omemo.signal.SignalOmemoService;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import java.io.IOException;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+
+public class SmackOmemoSignalIntegrationTestFramework {
+
+    public static void main(String[] args) throws InvalidKeyException, NoSuchPaddingException,
+                    InvalidAlgorithmParameterException, IllegalBlockSizeException,
+                    BadPaddingException, NoSuchAlgorithmException, NoSuchProviderException, SmackException,
+                    InterruptedException, CorruptedOmemoKeyException, KeyManagementException, IOException, XMPPException {
+        SignalOmemoService.acknowledgeLicense();
+        SignalOmemoService.setup();
+
+        final String[] smackOmemoPackages = new String[] { "org.jivesoftware.smackx.omemo" };
+        SmackIntegrationTestFramework.main(smackOmemoPackages);
+    }
+
+}

smack-omemo-signal-integration-test/src/main/java/org/igniterealtime/smack/inttest/smack_omemo_signal/package-info.java

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+/**
+ *
+ * Copyright 2017 Paul Schaub
+ *
+ * This file is part of smack-omemo-signal-integration-test.
+ *
+ * smack-omemo-signal-integration-test is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+ */
+
+/**
+ * The Smack Integration Test Framework for smack-omemo-signal.
+ */
+package org.igniterealtime.smack.inttest.smack_omemo_signal;