Catch PatternSyntaxException and add null checks

Adds null checks to pre- and suffixes and catches
PatternSyntaxExceptions at IRCCommandSender
Add option to toggle say and death message color

Also add PluginMetrics support
Refactor each command to another class file
Merge pull request #40 from ron975/master

Add null checks, making colouring say and death toggleable, refactor commands into separate class files, and add PluginMetrics support