Channel Join / Leave | AutoJoin | Default Channels | Mute/Unmute per Channel | Message Hook

New features
- Support for joining and leaving channels
- Support for configuration of a channel as default channel when more than one GLOBAL
- Support for channel AutoJoin being false and not join all channels on login
- Support for Mute/Unmute per Channel
- Support for notifying other plugins of a message being accepted into chat using TownyChatAsyncChatEvent
- Fixes ant build script to include line numbers when compiling

New Permissions
- towny.chat.leave.<channel name>
    Gives permission owner the ability to leave a channel
- townychat.mod.unmute
    Giver permission owner the ability to unmute people in any channel 
- townychat.mod.mute
    Giver permission owner the ability to mute people in any channel

All of the above require extra configuration to enable or disable. The default functionality is the same as the current TownyChat. 

If you'd prefer separate individual pull requests for each of the features let me know :-)