Update gradle and gradle android plugin

This is to support Android Studio 3

.travis.yml

@@ -4,7 +4,7 @@ sudo: true
 install:
 - echo y | android update sdk -u -a -t tools
 - echo y | android update sdk -u -a -t platform-tools
-- echo y | android update sdk -u -a -t build-tools-25.0.2
+- echo y | android update sdk -u -a -t build-tools-26.0.2
 - echo y | android update sdk -u -a -t android-25
 - echo y | android update sdk -u -a -t extra-google-m2repository
 - echo y | android update sdk -u -a -t extra-android-m2repository

app/build.gradle

@@ -8,7 +8,6 @@ findbugs {
 
 android {
     compileSdkVersion 25
-    buildToolsVersion "25.0.2"
 
     defaultConfig {
         applicationId "protect.card_locker"
@@ -30,6 +29,14 @@ android {
         disable "MissingTranslation"
     }
 
+    // Starting with Android Studio 3 Robolectric is unable to find resources.
+    // The following allows it to find the resources.
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
+
     // This is for Robolectric support for SDK 23
     useLibrary 'org.apache.http.legacy'
 }

build.gradle

@@ -3,9 +3,12 @@
 buildscript {
     repositories {
         jcenter()
+
+        // For the Android Gradle plugin
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.1.3'
+        classpath 'com.android.tools.build:gradle:3.0.1'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Sun Dec 04 15:17:03 EST 2016
+#Mon Dec 25 19:10:53 EST 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip