Update CI build configuration

Author: mgod

circle.yml

@@ -1,17 +1,20 @@
-checkout:
-  post:
-    - cp -r .circleci/licenses/. $ANDROID_HOME/licenses
-
 machine:
   java:
     version:
       oraclejdk8
 
-test:
+dependencies:
   pre:
-    - emulator -avd circleci-android24 -no-window:
-        background: true
-        parallel: true
+    # Android SDK Build-tools, revision 25.0.3, makes sure we've accepted the license
+    - if [ ! -d "/usr/local/android-sdk-linux/build-tools/25.0.3" ]; then echo y | android update sdk --no-ui --all --filter "build-tools-25.0.3"; fi
+  cache_directories:
+    - /usr/local/android-sdk-linux/build-tools/25.0.3
+  post:
+    - emulator -avd circleci-android22 -no-window:
+      background: true
+      parallel: true
+
+test:
   override:
     - ./gradlew test
     - circle-android wait-for-boot