Update to latest gradle

platform/android/build.gradle.template

@@ -3,7 +3,7 @@ buildscript {
 		jcenter()
 	}
 	dependencies {
-		classpath 'com.android.tools.build:gradle:2.1.0'
+		classpath 'com.android.tools.build:gradle:2.3.1'
 		$$GRADLE_CLASSPATH$$
 	}
 }

platform/android/java/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,7 @@
-#Wed Apr 10 15:27:10 PDT 2013
+#Fri May 12 08:50:03 KST 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-bin.zip
+org.gradle.jvmargs=-Xmx1536M