Update Gradle and Android, build improvements. Closes #1

build.gradle

@@ -11,11 +11,11 @@ buildscript {
   dependencies {
     classpath 'org.gradle.api.plugins:gradle-nexus-plugin:0.3'
 
-    classpath 'com.android.tools.build:gradle:1.0.1'
+    classpath 'com.android.tools.build:gradle:2.1.2'
 
     // for aar/maven stuff
-    // https://github.com/dcendents/android-maven-plugin
-    classpath 'com.github.dcendents:android-maven-plugin:1.2'
+    // https://github.com/dcendents/android-maven-gradle-plugin
+    classpath 'com.github.dcendents:android-maven-gradle-plugin:1.3'
   }
 }
 
@@ -23,10 +23,6 @@ def filterProjects(filter) {
   return subprojects.findAll { project -> filter.contains(project.name) }
 }
 
-task wrapper(type: Wrapper) {
-  gradleVersion = '2.3'
-}
-
 //apply from:'jdee.gradle'
 
 allprojects {
@@ -34,7 +30,7 @@ allprojects {
   version = '0.6.0-SNAPSHOT'
 
   ext.gdxVersion = "1.4.1"
-  ext.androidBuildVersionTools = "22"
+  ext.androidBuildVersionTools = "23.0.3"
 
   repositories {
     maven { url 'https://github.com/hjanetzek/maven-repo/raw/master/' }
@@ -51,7 +47,7 @@ allprojects {
 }
 
 def androidMinSdk() { return 10 }
-def androidTargetSdk() { return 21 }
+def androidTargetSdk() { return 23 }
 def versionCode() { return 50 }
 def versionName() { return version }