Make Android APK signed

.travis.yml

@@ -69,8 +69,8 @@ matrix:
         script:
           - cd android
           - ./gradlew assembleRelease
-          - mv app/build/outputs/apk/app-release-unsigned.apk ../deploy/sdlpal-release.apk
           - cd ..
+          - jarsigner -storetype pkcs12 -keystore winrt/SDLPal.UWP/SDLPal_TemporaryKey.pfx -signedjar deploy/sdlpal-release.apk -storepass "" android/app/build/outputs/apk/app-release-unsigned.apk 5f85e55b-6e81-4b08-ac2d-c51f3dae22ae
 
       - os: osx
         env: TARGET=iOS