Security channel mode fix, error-recovery and SAMODE improvements

This patch release of Oragono fixes a fairly big channel mode bug, where users could set channel modes when they weren't actually allowed to.

Config Changes

• recover-from-errors key added under debug, which enables recovery from client-caused errors (at the cost of possible server instability).

Security

• Clients could set channel modes when they weren't supposed to be able to.

Added

• We now allow recovering from client-caused panics.

Fixed

• SAMODE now lists other users' modes.
• Removed some possible crashes and races.