Gradle (#649)

* Gradle

Gradle support to make ease of import in Android Java projects.

* Gradle

Gradle support for Android projects.
For command line build, `gradle assembe` will trigger build phase

 - Config for Android .so file generation
 - Commented build.gradle
 - Automatic file copy after build
 - Dummy AndroidManifest file

* Build with Gradle

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

* Gradle Path

 - Absolute path for Gradle binary

* File check after Gradle build

 - Additional script for build success
 - Check the Gradle's `assemble.doLast` task

.gitignore

@@ -1,3 +1,14 @@
+.vscode/
+
+*.iml
+.idea/
+.externalNativeBuild/
+.gradle/
+gradle/
+gradlew*
+local.properties
+build/
+
 bin/
 /_CPack_Packages
 /CMakeScripts