BlockAlert

- Created error messages when using command in console. This is now fixed! - Changed the command structure to sub commands. - Added subcommand notification. This allows you to turn notifications on and off. - Added subcommand reload. This reloads the configuration file. No news, just relocated. - Added command version. Gives you information on which version BlockAlert is on. - Added new option in the configuration file that allows you to set the maximum block height for notifications on blocks. - Added new permission node blockalert.use for main command blockalert. - Added a list of subcommands that appear when you type the main command.