General Project update

[JonatanSalas]

• Updated gradle build files and gradle plugin
• Updated app demo code example to improve code readability
• RippleConfig setters acts as builder
• Added config folder and configure plugins to check code style, possible bugs, etc.
• Other minimal improvements

Thanks for your project! It's really cool. I have been improving some things because I want to add your project as dependency of my project material-calendar-view!