restore android build tools version and fix travis android release

Author: Richard-Cao

.travis.yml

@@ -62,7 +62,7 @@ script:
 # been resolved.
 - if [[ $TEST_TYPE == 'ios' ]]; then xcodebuild -project ios/$PROJECT_MOBILE.xcodeproj
   -scheme $PROJECT_MOBILE -sdk iphonesimulator9.3 -configuration Debug CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO clean build ; fi
-- if [ $TEST_TYPE == 'android' ] && [ $TRAVIS_PULL_REQUEST == 'false' ]; then cd android && ./gradlew clean && ./gradlew resguard --stacktrace ; fi
+- if [ $TEST_TYPE == 'android' ] && [ $TRAVIS_PULL_REQUEST == 'false' ]; then cd android && ./gradlew clean && ./gradlew resguardRelease --stacktrace ; fi
 - if [ $TEST_TYPE == 'android' ] && [ $TRAVIS_PULL_REQUEST != 'false' ]; then cd android && ./gradlew clean && ./gradlew assembleDebug --stacktrace ; fi
 after_success:
 - if [ $TEST_TYPE == 'android' ] && [ $TRAVIS_PULL_REQUEST == 'false' ]; then fir p 

android/app/build.gradle

@@ -90,7 +90,7 @@ def enableProguardInReleaseBuilds = true
 
 android {
     compileSdkVersion 23
-    buildToolsVersion "23.0.3"
+    buildToolsVersion "23.0.1"
     useLibrary 'org.apache.http.legacy'
 
     defaultConfig {
@@ -147,7 +147,7 @@ android {
     }
 }
 
-andResGuard {   // ./gradlew resguard
+andResGuard {   // ./gradlew resguard[BuildType | Flavor]
     mappingFile = null
     use7zip = true
     useSign = true