Merge pull request #75 from Hoikas/messages

Moar Messages
Merge pull request #74 from Hoikas/concurrency

Concurrency Part 2
Add basic account flags

- We now support banning accounts
- Admins can now send messages that aren't safe for networking
Add modacct console command
Implement restricted logins

This is useful for times when you want to control the access to your shard. For example, immediately after an update.