Commands overhaul

[voidpointer0x00]

Naming:

• /whitelist remove|rem -> /whitelist remove|rm 💯
• /whitelist status -> /whitelist is-on 💯
• /whitelist info (player) -> /whitelist get (player) ❓
• /whitelist on|off -> /whitelist on|off|enable|disable ❓

Behaviour:

• Sub commands TabComplete should not suggest aliases, although should complete.
  Perhaps, it should be possible to control whether some alliases are suggestable or not. (pretty easy to implement and seems convenient)

Libraries:
Commands in the future should automatically handle any exceptions. That would also involve a new Exception type that would allow commands to throw an exception with a specific message from locale module.

Switching to Aikair's Command Framework should also be considered.