Mavenize.
Move exceptions to .ex
Add logging dependency and define plugin versions
Name variables
Switch logging to SLF4j
Private final -> just private is enough
Bug risk comment
Split event handler and the bot engine.
Finish splitting event handler and the bot engine.
Move util methods to Utils.
Finish porting logging to slf4j.
Remove useless version tags.
Rename the PircBot class to IrcServerConnection.