Build with Gradle

- Build job for Travis CI
 - Moved gradle file to support/

.travis.yml

@@ -21,6 +21,34 @@ matrix:
   exclude:
     - os: osx
       env: BUILD=Doc
+  include:
+    - language: android
+      android:
+      components:
+        - tools
+        - platform-tools
+        - android-21
+        - sys-img-armeabi-v7a-android-21
+      env:
+        - ANDROID_ARCH_NAME=arm
+        - ANDROID_ABI=armeabi-v7a
+      before_install:
+        - git submodule update --init --recursive
+        - sudo apt-get install wget unzip tree
+      install:
+        # Accept SDK Licenses + Install NDK
+        - yes | sdkmanager --update > /dev/null 2>&1
+        - sdkmanager ndk-bundle > /dev/null 2>&1
+        # Download Gradle 4.3.1 
+        - wget https://services.gradle.org/distributions/gradle-4.3.1-bin.zip
+        - mkdir -p gradle
+        - unzip -q -d ./gradle gradle-4.3.1-bin.zip
+        - export GRADLE=gradle/gradle-4.3.1/bin/gradle
+      before_script:
+        - bash $GRADLE --version
+        - cd ./support
+      script:
+        - bash $GRADLE clean assemble
 
 # Install gcc-6 for extended constexpr support.
 addons:

support/build.gradle

@@ -60,7 +60,7 @@ android {
     //    neighbor of the top level cmake
     externalNativeBuild {
         cmake {
-            path "CMakeLists.txt"
+            path "../CMakeLists.txt"
             // buildStagingDirectory "./build"  // Custom path for cmake output
         }
         //println(cmake.path)
@@ -69,7 +69,7 @@ android {
     sourceSets{
         // Android Manifest for Gradle
         main {
-            manifest.srcFile 'support/AndroidManifest.xml'
+            manifest.srcFile 'AndroidManifest.xml'
         }
     }
 }