Bump buildTools, sdkVersion and dependencies

Test changes were required since RxJava 1.1.6 changed the way
ReplaySubject in a way that broke reusing the same `TestSubscriber` more
than once. (See comments here:
ReactiveX/RxJava#4225 (comment))
Fixed tests by using a `TestObserver` that can be reused multiple times.

build.gradle

@@ -6,7 +6,7 @@ buildscript {
   }
   dependencies {
     classpath 'com.bmuschko:gradle-nexus-plugin:2.3.1'
-    classpath 'com.android.tools.build:gradle:2.1.0'
+    classpath 'com.android.tools.build:gradle:2.1.3'
     classpath 'me.tatarka.retrolambda.projectlombok:lombok.ast:0.2.3.a2'
   }
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Tue Sep 15 12:05:54 PDT 2015
+#Sat Aug 27 18:56:48 PDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.13-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-all.zip

rxgroups-android/build.gradle

@@ -2,26 +2,26 @@ apply plugin: 'com.android.library'
 apply from: 'gradle-maven-push.gradle'
 
 android {
-  compileSdkVersion 23
-  buildToolsVersion "23.0.2"
+  compileSdkVersion 24
+  buildToolsVersion "24.0.2"
 
   defaultConfig {
     minSdkVersion 16
-    targetSdkVersion 23
+    targetSdkVersion 24
   }
 }
 
 dependencies {
   compile project(':rxgroups')
-  compile 'io.reactivex:rxandroid:1.2.0'
+  compile 'io.reactivex:rxandroid:1.2.1'
 
   testCompile "junit:junit:4.12"
   testCompile 'org.mockito:mockito-core:1.10.19'
   testCompile "org.hamcrest:hamcrest-integration:1.3"
   testCompile "org.hamcrest:hamcrest-core:1.3"
   testCompile "org.hamcrest:hamcrest-library:1.3"
   testCompile 'org.assertj:assertj-core:1.7.0'
-  testCompile("org.robolectric:robolectric:3.0") {
+  testCompile("org.robolectric:robolectric:3.1.2") {
     exclude module: 'classworlds'
     exclude module: 'commons-logging'
     exclude module: 'httpclient'

rxgroups/build.gradle

@@ -15,7 +15,7 @@ project.group = GROUP
 project.version = VERSION_NAME
 
 dependencies {
-  compile 'io.reactivex:rxjava:1.1.5'
+  compile 'io.reactivex:rxjava:1.1.9'
   compile 'com.google.code.findbugs:jsr305:3.0.0'
 
   testCompile 'junit:junit:4.12'