Update project setup

* Use Gradle wrapper to ensure reproduceable build on various machines.
* Do not track IDE specific files from IntelliJ or Android Studio. Please note, that I **deleted** the `GraphView.iml` file. It can be easily recreated via Android Studio. Close the project, then remove the `.idea` folder and all `.iml` files, then re-import the project. 
* Fixed deployment script - Gradle did not work at all since the `isReleaseBuild()` function and environment variables were missing.