Upgrade Gradle version from 2.5 to 2.11

Tested most of the build features
diff --git a/build.gradle b/build.gradle
index df6eeb6..f9298c4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1033,5 +1033,5 @@
 //  2) /gradlew.bat which is the windows bat script for for executing builds
 //  3) /gradle/wrapper which is a directory named by the "jarPath" config which contains other needed files.
 task wrapper( type: Wrapper ) {
-  gradleVersion = '2.5'
+  gradleVersion = '2.11'
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 48f202a..fafa8dd 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.5-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.11-bin.zip