Process client arguments, Auto login option

Created by: RedSparr0w

Info:

Added three possible arguments for launching client: server, username, password.

Aliases:

• server:
  • -s
  • -server
• username:
  • -u
  • -user
  • -username
• password:
  • -p
  • -pass
  • -password

Example:

Testing on local:

java -jar client.jar -server localhost -u myusername -p mypassword

NOTE: Also fixed up the server XP rate, must have changed it by accident in one of the other PRs 😅