Hey,
it seems like they renamed "org.openqa.grid.selenium.GridLauncher" to "org.openqa.grid.selenium.GridLauncherV3".
I was trying to run the selenium grid for the first time with help of the
Selendroid guide with the latest "selenium-server-standalone-3.0.1.jar" and I kept getting error: "Error: Could not find or load main class org.openqa.grid.selenium.GridLauncher".
Don't know if they renamed it on purpose, but your guide may need updating.