Add curator-recipes to SBT library dependencies.
Build fix.

[error] /home/travis/build/SollmoStudio/beyond/app/beyond/plugin/GamePlugin.scala:18:
not enough arguments for constructor BeyondContextFactory: (config: beyond.plugin.BeyondContextFactoryConfig)beyond.plugin.BeyondContextFactory.
[error] Unspecified value parameter config.
[error]   private val contextFactory: BeyondContextFactory = new BeyondContextFactory
[error]                                                      ^
Rename ZookeeperLauncherCommand to ZooKeeperLauncherCommand.
Launch MongoDB server.

Add MongoDBLauncher actor which manages the lifecycle of MongoDB server.
Override Actor lifecycle methods to launch and shutdown server.

The lifecycle of the underlying server is always the same as that of its actor.
So there is no need for separate Launch or Shutdown messages.
Use time unit seconds in timeout value.

It is more readable to use time units such as seconds in timeout value.
Add LauncherSupervisor to monitor the lifecycle of launchers.

LauncherSupervisor creates two child actors and monitor them.
- mongoDBLauncher
- zooKeeperLauncher
Wait for ZooKeeper server startup and shutdown.

Make ZooKeeperLauncher wait for server startup and shutdown by sending "stat"
command and check if the server responds.
Redirect to the index page if a user is already logged in.
Add logout page and logout button on header.