Describe setup process for repositories

[lukashaertel]

There's no description of how to include the project. I had to fiddle around a bit to find out what Maven repositories to add. It might be a good idea to display that somewhere in the readme file.

My build.gradle.kts:

repositories {
    jcenter()
    maven("https://jitpack.io")
    maven("http://maven.imagej.net")
    maven("http://maven.imagej.net/content/repositories/releases/")
    maven("http://maven.imagej.net/content/repositories/public/")
}

dependencies {
    compile(kotlin("stdlib-jdk8"))
    compile("com.github.holgerbrandl:kip:9ee71b76b3")
}