feat(android/build.gradle): add build.gradle to fix gradle plugin version issue

Author: benmarten

LeanplumSample/Assets/Plugins/Android/mainTemplate.gradle

@@ -0,0 +1,51 @@
+// GENERATED BY Leanplum.
+buildscript {
+	repositories {
+		jcenter()
+	}
+
+	dependencies {
+		classpath 'com.android.tools.build:gradle:2.3.1'
+	}
+}
+
+allprojects {
+   repositories {
+      flatDir {
+        dirs 'libs'
+      }
+   }
+}
+
+apply plugin: 'com.android.application'
+
+dependencies {
+	compile fileTree(dir: 'libs', include: ['*.jar'])
+}
+
+android {
+	compileSdkVersion 25
+	buildToolsVersion '25.0.2'
+
+	defaultConfig {
+		targetSdkVersion 25
+	}
+
+	lintOptions {
+		abortOnError false
+	}
+
+	buildTypes {
+		debug {
+			jniDebuggable true
+		}
+		release {
+			// Set minifyEnabled to true if you want to run ProGuard on your project
+			minifyEnabled false
+			proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-unity.txt'
+			
+		}
+	}
+
+}
+

build.sh

@@ -5,10 +5,6 @@
 #
 set -eo pipefail; [[ $DEBUG ]] && set -x
 
-# Copied from "$LPM_PLUGIN_PATH/_common/constants.sh"
-UNITY_VERSION=1.4.2-SNAPSHOT
-
-# Copied from "$LPM_PLUGIN_PATH/_common/functions.sh"
 #######################################
 # Downloads the iOS SDK from internal repository.
 # Globals:
@@ -117,7 +113,7 @@ build() {
   PATH_TO_PROJECT="$(pwd)/LeanplumSample"
 
   OUT_DLL="$PATH_TO_PROJECT/Assets/Standard Assets/Leanplum/LeanplumSDK.dll"
-  export OUT_PKG="Leanplum_Unity-$UNITY_VERSION_STRING.unitypackage"
+  export OUT_PKG="Leanplum_Unity-${UNITY_VERSION_STRING}.unitypackage"
 
   # Compile dll and place into project.
   $PATH_TO_UNITY_ROOT/Contents/Mono/bin/gmcs -r:"$PATH_TO_UNITYENGINE" \