Remove Channel class

Since we only support one channel, there is not need to have a whole
class or a hashmap dedicated to supporting multiple channels.
Add sendAll function

Since sending to all players in IRC.channel is such a common idiom, make
a function out of it
Add sendError function
Initialize startTime when starting
Move argmodes into variable declaration block
Make assignment of class variables idiomatic
Rewrite FMODE handling

No need to parse modes since we aren't doing bans. So just pass the mode
change to the users.
Rewrite PRIVMSG handling
Add User class
Rewrite KICK handling
Add sender where applicable
Add comments explaining each command's arguments
Add handling for NICK
Add handling for KILL
Add handling for NOTICE
Check newnick before using it

Otherwise any user can cause a netsplit!
Make PMReplyCommand a wrapper around PMCommand

Because why have mostly the same code twice?
Correctly handle /me
Generate SID from server info

This mirrors the code InspIRCd uses to generate SIDs.
Remove countChar function