java: Publish 2.1.6 to maven and bintray

Note: Needed a minor patch in x/ref to make this compile
-       v23_syncbase_Init()
+       v23_syncbase_Init(C.v23_syncbase_Bool(1))

in services/syncbase/bridge/cgo/jni.go

Changes covered:
- RPC can now switch endpoints automatically if a connection has been
  lost.
- Sync speed is vastly improved due to more frequent gen vector cuts.

Change-Id: Ia10cac1e967a3b32c8f2a576e8c6836b0f12ca82
diff --git a/android-lib/build.gradle b/android-lib/build.gradle
index 0330a08..e3594f5 100644
--- a/android-lib/build.gradle
+++ b/android-lib/build.gradle
@@ -30,7 +30,7 @@
 
 // You should change this after releasing a new version of the library. See the
 // list of published versions at https://repo1.maven.org/maven2/io/v/vanadium-android.
-def releaseVersion = '2.1.5'
+def releaseVersion = '2.1.6'
 
 android {
     buildToolsVersion '23.0.1'
diff --git a/lib/build.gradle b/lib/build.gradle
index 1a27b83..9a8cf49 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -23,7 +23,7 @@
 
 // You should change this after releasing a new version of the library. See the
 // list of published versions at https://repo1.maven.org/maven2/io/v/vanadium.
-def releaseVersion = '2.1.5'
+def releaseVersion = '2.1.6'
 
 dependencies {
     compile group: 'joda-time', name: 'joda-time', version: '2.7'