Fix javadoc
Shuffle Jansi/Jline versions
Add ping throttle

Sending a handshake and a bunch of StatusRequests is a very effective
DDoS attack because each SR is just one x00 byte and the StatusRequest
handler is quite CPU-intensive. This PR adds a configurable limit to
disconnect a client after they have pinged a certain amount of times per
connection. Setting it to -1 disables this throttle. Defaults to 5
because I can't think of any use case beyond two and it appears to
reasonably protect against this exploit.
Track plugin classloader to use plugin thread group where possible

This commit allows creation of threads in most plugin use cases where it
was previously restricted because of the new security manager. To
accomplish this, the security manager resolves the ClassLoader that is
attempting to create the thread and links it to its plugin to finally
return that plugin's thread group. Specifically, this resolves issues
when trying to create threads and ThreadFactories in places other than
BungeeScheduler.runAsync such as Plugin.onEnable.
Add LoginCancelEvent to catch disconnects during login