Handle connection closure

[OscarFKE]

Handle the connection to the IRC server closing by cleanly closing DB connection and exiting the process. Changed scheduled event deactivation logic as events were not being reactivated on rejoining a room. Added kick handler to deactivate scheduled events for the channel mockturtle was kicked from.

[pushcx]

@OscarFKE and I talked through this on IRC, we're going to try a simpler approach in #20 and hang onto this in case anything requires the manual tidying.