Add SetNetGroupIdMsg

This fixes the visually displeasing kicable-fighting when a non-game master kicks a physical
Add ControlEventMsg (for console commands)
Merge pull request #75 from Hoikas/messages

Moar Messages
Add some more cases that allow for net-sucking
Protect socket sends now that they might be many-step operations
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.
Correct locks in `dm_propagate_to`
Add missing lock to `DS::GameServer_DisplayClients`
Merge pull request #77 from Hoikas/locks

Add Missing Locks
Merge pull request #76 from Hoikas/acct-flags

Basic Account Flags
Add configuration option to disable the status server